Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Solution of the homogeneous equation. y ′′ + 4 y ′ + 4 y = 0 λ 2 e λ x + 4 λ e λ x + 4 e λ x = 0 λ 2 + 4 λ + 4 = 0 √ − 4 ± 16 − 16 = = − 2 λ 1 , 2 2 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Solution of the homogeneous equation. y ′′ + 4 y ′ + 4 y = 0 λ 2 e λ x + 4 λ e λ x + 4 e λ x = 0 λ 2 + 4 λ + 4 = 0 √ − 4 ± 16 − 16 = = − 2 λ 1 , 2 2 c 1 e − 2 x + c 2 xe − 2 x = y h logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the Wronskian. e − 2 t � e − 2 t − 2 te − 2 t � − te − 2 t � − 2 e − 2 t � W ( y 1 , y 2 )( t ) = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the Wronskian. e − 2 t � e − 2 t − 2 te − 2 t � − te − 2 t � − 2 e − 2 t � W ( y 1 , y 2 )( t ) = e − 4 t − 2 te − 4 t + 2 te − 4 t = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the Wronskian. e − 2 t � e − 2 t − 2 te − 2 t � − te − 2 t � − 2 e − 2 t � W ( y 1 , y 2 )( t ) = e − 4 t − 2 te − 4 t + 2 te − 4 t = e − 4 t = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 1 ( t ) dt W ( y 1 , y 2 )( t ) logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) sin ( t ) 1 1 � � e − 2 t dt a 2 ( t ) y 1 ( t ) dt = W ( y 1 , y 2 )( t ) e − 4 t 1 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) sin ( t ) 1 1 � � e − 2 t dt a 2 ( t ) y 1 ( t ) dt = W ( y 1 , y 2 )( t ) e − 4 t 1 � e 2 t sin ( t ) dt = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � e 2 t sin ( t ) dt logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t sin ( t ) dt 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t sin ( t ) dt 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = � 1 � 1 � 1 2 e 2 t sin ( t ) − 1 2 e 2 t cos ( t ) − 2 e 2 t � � = − sin ( t ) dt 2 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t sin ( t ) dt 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = � 1 � 1 � 1 2 e 2 t sin ( t ) − 1 2 e 2 t cos ( t ) − 2 e 2 t � � = − sin ( t ) dt 2 1 2 e 2 t sin ( t ) − 1 4 e 2 t cos ( t ) − 1 � e 2 t sin ( t ) dt = 4 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t sin ( t ) dt 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = � 1 � 1 � 1 2 e 2 t sin ( t ) − 1 2 e 2 t cos ( t ) − 2 e 2 t � � = − sin ( t ) dt 2 1 2 e 2 t sin ( t ) − 1 4 e 2 t cos ( t ) − 1 � e 2 t sin ( t ) dt = 4 5 1 2 e 2 t sin ( t ) − 1 � e 2 t sin ( t ) dt 4 e 2 t cos ( t ) = 4 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t sin ( t ) dt 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = � 1 � 1 � 2 e 2 t sin ( t ) − 1 1 2 e 2 t cos ( t ) − 2 e 2 t � � = − sin ( t ) dt 2 1 2 e 2 t sin ( t ) − 1 4 e 2 t cos ( t ) − 1 � e 2 t sin ( t ) dt = 4 5 1 2 e 2 t sin ( t ) − 1 � e 2 t sin ( t ) dt 4 e 2 t cos ( t ) = 4 2 5 e 2 t sin ( t ) − 1 � e 2 t sin ( t ) dt 5 e 2 t cos ( t ) = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) sin ( t ) 1 � te − 2 t dt = e − 4 t 1 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) sin ( t ) 1 � te − 2 t dt = e − 4 t 1 � te 2 t sin ( t ) dt = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) sin ( t ) 1 � te − 2 t dt = e − 4 t 1 � te 2 t sin ( t ) dt = � 2 � 2 � 5 e 2 t sin ( t ) − 1 5 e 2 t sin ( t ) − 1 5 e 2 t cos ( t ) 5 e 2 t cos ( t ) dt = t − logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) sin ( t ) 1 � te − 2 t dt = e − 4 t 1 � te 2 t sin ( t ) dt = � 2 � 2 � 5 e 2 t sin ( t ) − 1 5 e 2 t sin ( t ) − 1 5 e 2 t cos ( t ) 5 e 2 t cos ( t ) dt = t − 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 e 2 t sin ( t ) dt + 1 � � e 2 t cos ( t ) dt = 5 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � e 2 t cos ( t ) dt logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t cos ( t ) dt 2 e 2 t cos ( t )+ 2 e 2 t sin ( t ) dt = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t cos ( t ) dt 2 e 2 t cos ( t )+ 2 e 2 t sin ( t ) dt = � 1 � 1 � 1 2 e 2 t cos ( t )+ 1 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = 2 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t cos ( t ) dt 2 e 2 t cos ( t )+ 2 e 2 t sin ( t ) dt = � 1 � 1 � 2 e 2 t cos ( t )+ 1 1 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = 2 1 2 e 2 t cos ( t )+ 1 4 e 2 t sin ( t ) − 1 � e 2 t cos ( t ) dt = 4 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t cos ( t ) dt 2 e 2 t cos ( t )+ 2 e 2 t sin ( t ) dt = � 1 � 1 � 1 2 e 2 t cos ( t )+ 1 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = 2 1 2 e 2 t cos ( t )+ 1 4 e 2 t sin ( t ) − 1 � e 2 t cos ( t ) dt = 4 5 1 2 e 2 t cos ( t )+ 1 � e 2 t cos ( t ) dt 4 e 2 t sin ( t ) = 4 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. � 1 1 � e 2 t cos ( t ) dt 2 e 2 t cos ( t )+ 2 e 2 t sin ( t ) dt = � 1 � 1 � 1 2 e 2 t cos ( t )+ 1 2 e 2 t sin ( t ) − 2 e 2 t cos ( t ) dt = 2 1 2 e 2 t cos ( t )+ 1 4 e 2 t sin ( t ) − 1 � e 2 t cos ( t ) dt = 4 5 1 2 e 2 t cos ( t )+ 1 � e 2 t cos ( t ) dt 4 e 2 t sin ( t ) = 4 2 5 e 2 t cos ( t )+ 1 � e 2 t cos ( t ) dt 5 e 2 t sin ( t ) = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 e 2 t sin ( t ) dt + 1 � � e 2 t cos ( t ) dt = 5 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 e 2 t sin ( t ) dt + 1 � � e 2 t cos ( t ) dt = 5 5 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) 5 te 2 t sin ( t ) − 1 2 5 te 2 t cos ( t ) − 2 e 2 t sin ( t ) dt + 1 � � e 2 t cos ( t ) dt = 5 5 � 2 � 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 5 e 2 t sin ( t ) − 1 5 e 2 t cos ( t ) = 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 e 2 t sin ( t ) dt + 1 � � e 2 t cos ( t ) dt = 5 5 � 2 � 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 5 e 2 t sin ( t ) − 1 5 e 2 t cos ( t ) = 5 � 2 � + 1 5 e 2 t cos ( t )+ 1 5 e 2 t sin ( t ) 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Computing the integrals. f ( t ) 1 � a 2 ( t ) y 2 ( t ) dt W ( y 1 , y 2 )( t ) 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 e 2 t sin ( t ) dt + 1 � � e 2 t cos ( t ) dt = 5 5 � 2 � 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 2 5 e 2 t sin ( t ) − 1 5 e 2 t cos ( t ) = 5 � 2 � + 1 5 e 2 t cos ( t )+ 1 5 e 2 t sin ( t ) 5 2 5 te 2 t sin ( t ) − 1 5 te 2 t cos ( t ) − 3 25 e 2 t sin ( t )+ 4 25 e 2 t cos ( t ) = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Stating the general solution. logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Stating the general solution. � x � x f ( t ) f ( t ) 1 1 y p = − y 1 ( x ) a 2 ( t ) y 2 ( t ) dt + y 2 ( x ) a 2 ( t ) y 1 ( t ) dt W ( y 1 , y 2 )( t ) W ( y 1 , y 2 )( t ) x 0 x 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Stating the general solution. � x � x f ( t ) f ( t ) 1 1 y p = − y 1 ( x ) a 2 ( t ) y 2 ( t ) dt + y 2 ( x ) a 2 ( t ) y 1 ( t ) dt W ( y 1 , y 2 )( t ) W ( y 1 , y 2 )( t ) x 0 x 0 � 2 � 5 xe 2 x sin ( x ) − 1 5 xe 2 x cos ( x ) − 3 25 e 2 x sin ( x )+ 4 25 e 2 x cos ( x ) = − e − 2 x logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Stating the general solution. � x � x f ( t ) f ( t ) 1 1 y p = − y 1 ( x ) a 2 ( t ) y 2 ( t ) dt + y 2 ( x ) a 2 ( t ) y 1 ( t ) dt W ( y 1 , y 2 )( t ) W ( y 1 , y 2 )( t ) x 0 x 0 � 2 � 5 xe 2 x sin ( x ) − 1 5 xe 2 x cos ( x ) − 3 25 e 2 x sin ( x )+ 4 25 e 2 x cos ( x ) = − e − 2 x � 2 � 5 e 2 x sin ( x ) − 1 5 e 2 x cos ( x ) + xe − 2 x logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Stating the general solution. � x � x f ( t ) f ( t ) 1 1 y p = − y 1 ( x ) a 2 ( t ) y 2 ( t ) dt + y 2 ( x ) a 2 ( t ) y 1 ( t ) dt W ( y 1 , y 2 )( t ) W ( y 1 , y 2 )( t ) x 0 x 0 � 2 � 5 xe 2 x sin ( x ) − 1 5 xe 2 x cos ( x ) − 3 25 e 2 x sin ( x )+ 4 25 e 2 x cos ( x ) = − e − 2 x � 2 � 5 e 2 x sin ( x ) − 1 5 e 2 x cos ( x ) + xe − 2 x 25 sin ( x ) − 4 3 = 25 cos ( x ) logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Stating the general solution. � x � x f ( t ) f ( t ) 1 1 y p = − y 1 ( x ) a 2 ( t ) y 2 ( t ) dt + y 2 ( x ) a 2 ( t ) y 1 ( t ) dt W ( y 1 , y 2 )( t ) W ( y 1 , y 2 )( t ) x 0 x 0 � 2 � 5 xe 2 x sin ( x ) − 1 5 xe 2 x cos ( x ) − 3 25 e 2 x sin ( x )+ 4 25 e 2 x cos ( x ) = − e − 2 x � 2 � 5 e 2 x sin ( x ) − 1 5 e 2 x cos ( x ) + xe − 2 x 25 sin ( x ) − 4 3 = 25 cos ( x ) y = − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = 1 = y ( 0 ) logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 1 = 25 + c 1 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 y ′ ( 0 ) = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 y ′ ( 0 ) = 3 = 25 − 2 c 1 + c 2 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 y ′ ( 0 ) = 3 c 2 = 2 c 1 − 3 = 25 − 2 c 1 + c 2 , 0 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 y ′ ( 0 ) = 3 c 2 = 2 c 1 − 3 25 = 55 = 25 − 2 c 1 + c 2 , 0 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 y ′ ( 0 ) = 3 c 2 = 2 c 1 − 3 25 = 55 25 = 11 = 25 − 2 c 1 + c 2 , 0 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 Finding c 1 , c 2 . − 4 25 cos ( x )+ 3 25 sin ( x )+ c 1 e − 2 x + c 2 xe − 2 x = y 25 sin ( x )+ 3 4 25 cos ( x ) − 2 c 1 e − 2 x + c 2 � e − 2 x − 2 xe − 2 x � y ′ = y ( 0 ) = − 4 c 1 = 29 1 = 25 + c 1 , 25 y ′ ( 0 ) = 3 c 2 = 2 c 1 − 3 25 = 55 25 = 11 = 25 − 2 c 1 + c 2 , 0 5 − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x = y logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Solve the Initial Value Problem y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0 y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 � � − 16 25 + 12 25 + 4 cos ( x ) 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 � � � 12 � − 16 25 + 12 25 + 4 25 + 16 25 − 3 cos ( x )+ sin ( x ) 25 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 � � � 12 � − 16 25 + 12 25 + 4 25 + 16 25 − 3 cos ( x )+ sin ( x ) 25 25 � 116 � 25 − 232 25 + 44 5 + 116 25 − 44 e − 2 x + 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 � � � 12 � − 16 25 + 12 25 + 4 25 + 16 25 − 3 cos ( x )+ sin ( x ) 25 25 � 116 � � 44 � 25 − 232 25 + 44 5 + 116 25 − 44 5 − 88 5 + 44 e − 2 x + xe − 2 x + 5 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 � � � 12 � − 16 25 + 12 25 + 4 25 + 16 25 − 3 cos ( x )+ sin ( x ) 25 25 � 116 � � 44 � 25 − 232 25 + 44 5 + 116 25 − 44 5 − 88 5 + 44 ? e − 2 x + xe − 2 x + = sin ( x ) 5 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? � � − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x 4 � 4 e − 2 x − 2 xe − 2 x �� 25 sin ( x )+ 3 25 cos ( x ) − 58 25 e − 2 x + 11 � + 4 5 + 4 25 cos ( x ) − 3 25 sin ( x )+ 116 25 e − 2 x + 11 − 4 e − 2 x + 4 xe − 2 x � ? � = sin ( x ) 5 � � � 12 � − 16 25 + 12 25 + 4 25 + 16 25 − 3 cos ( x )+ sin ( x ) 25 25 √ � 116 � � 44 � 25 − 232 25 + 44 5 + 116 25 − 44 5 − 88 5 + 44 e − 2 x + xe − 2 x + = sin ( x ) 5 5 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? − 4 25 + 29 y ( 0 ) = 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? − 4 25 + 29 y ( 0 ) = 25 = 1 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 25 sin ( x )+ 3 4 25 cos ( x ) − 58 25 e − 2 x + 55 � e − 2 x − 2 xe − 2 x � y ′ ( x ) = 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 25 sin ( x )+ 3 4 25 cos ( x ) − 58 25 e − 2 x + 55 � e − 2 x − 2 xe − 2 x � y ′ ( x ) = 25 25 − 58 3 25 + 55 y ′ ( 0 ) = 25 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 25 sin ( x )+ 3 4 25 cos ( x ) − 58 25 e − 2 x + 55 � e − 2 x − 2 xe − 2 x � y ′ ( x ) = 25 25 − 58 3 25 + 55 y ′ ( 0 ) = 25 = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 25 sin ( x )+ 3 4 25 cos ( x ) − 58 25 e − 2 x + 55 � e − 2 x − 2 xe − 2 x � y ′ ( x ) = 25 25 − 58 3 25 + 55 √ y ′ ( 0 ) = 25 = 0 logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 25 sin ( x )+ 3 4 25 cos ( x ) − 58 25 e − 2 x + 55 � e − 2 x − 2 xe − 2 x � y ′ ( x ) = 25 25 − 58 3 25 + 55 √ y ′ ( 0 ) = 25 = 0 Alternatively, use a computer to double check the result. logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Does y = − 4 25 cos ( x )+ 3 25 sin ( x )+ 29 25 e − 2 x + 11 5 xe − 2 x Solve y ′′ + 4 y ′ + 4 y = sin ( x ) , y ( 0 ) = 1, y ′ ( 0 ) = 0? √ − 4 25 + 29 y ( 0 ) = 25 = 1 25 sin ( x )+ 3 4 25 cos ( x ) − 58 25 e − 2 x + 55 � e − 2 x − 2 xe − 2 x � y ′ ( x ) = 25 25 − 58 3 25 + 55 √ y ′ ( 0 ) = 25 = 0 Alternatively, use a computer to double check the result. Beyond a certain level of complexity, that really is the way to go. logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Double Checking with a Computer Algebra System logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
Overview An Example Double Check Further Discussion Double Checking with a Computer Algebra System logo1 Bernd Schr¨ oder Louisiana Tech University, College of Engineering and Science Variation of Parameters
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