Undetermined coefficients help

[brungus]

Hi, new here, I am looking for some help on this homework problem. pretty sure you need to separate yp into 2 parts?

anyways, use method of undetermined coeff. to solve

y" + y = x*cos(x) - cos(x)

thanks.

 

[Hootenanny]

Hi, new here, I am looking for some help on this homework problem. pretty sure you need to separate yp into 2 parts?

anyways, use method of undetermined coeff. to solve

y" + y = x*cos(x) - cos(x)

thanks.

Hi brungus and welcome to PF,

I'm assuming that you've found the homogeneous solution. For the particular solution, notice that we have a product of two functions of x. How does one usually differentiate a product of two functions?

Also for future reference, we have Homework Forums where you can post all your textbook questions .

 

[HallsofIvy]

Why have you not shown any work? In particular, what do you get for the general solution to the corresponding homogeneous equation?