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For what value of k, if any, is y=e−2x+ke4x a solution to the differential equation y−y′′4=5e4x ?

Respuesta :

Applying substitution, it is found that y is a solution to the differential equation for k = 1.

What is the differential equation:

It is given by:

[tex]y - \frac{y^{\prime\prime}}{4} = 5e^{4x}[/tex]

We are testing the following solution:

[tex]y = e^{-2x} + ke^{4x}[/tex]

It's derivatives are given by:

[tex]y^{\prime}(x) = -2e^{-2x} + 4ke^{4x}[/tex]

[tex]y^{\prime\prime}(x) = 4e^{-2x} + 16ke^{4x}[/tex]

Then, replacing in the differential equation:

[tex]y - \frac{y^{\prime\prime}}{4} = 5e^{4x}[/tex]

[tex]e^{-2x} + ke^{4x} - \frac{4e^{-2x} + 16ke^{4x}}{4} = 5e^{4x}[/tex]

[tex]e^{-2x} + ke^{4x} - e^{-2x} + 4ke^{4x} = 5e^{4x}[/tex]

[tex]5ke^{4x} = 5e^{4x}[/tex]

[tex]5k = 5[/tex]

[tex]k = 1[/tex]

Then, y is a solution to the differential equation for k = 1.

More can be learned about differential equations at https://brainly.com/question/14423176