OpenStudy (anonymous):

When finding the particular solution to x'' + 4x = sin(x) + cos(x) can I use undetermined coefficients?

4 years ago
OpenStudy (anonymous):

I think so. Though, are you sure that's x''+4x and not y''+4y?

4 years ago
OpenStudy (anonymous):

Probably, I interchange them constantly. If you do you undetermined coeff, then are you familiar with the process of spiting up the right side of the equation to make the method of finding the particular easier?

4 years ago
OpenStudy (anonymous):

O, wait the equation is x'' + 4x = sin(t) + cos(t)

4 years ago
OpenStudy (anonymous):

Ah, ok. Yes, You can assume that the particular is some combination of sines and cosines, such as Asin(t) + Bcos(t).

4 years ago
OpenStudy (anonymous):

See http://tutorial.math.lamar.edu/Classes/DE/UndeterminedCoefficients.aspx for more examples.

4 years ago