Find $y_p(x)$ if
$y^{(4)} - 5y'' + 4y = e^x(42 + 42x - 18x^2)$.
First input the form of $y_p(x)$ to make sure you are ready to proceed. Use A, B, C.. as coefficients (skipping
no letters).
The form of $y_p(x)$ is
$\frac{e^x(-3x^3 + 9x^2 + 12x + 11)}{3}$
Now solve for the undetermined coefficients to find $y_p(x) = \frac{e^x(-3x^3 + 9x^2 + 12x + 11)}{3}$