We are given with the equation y"+ 9 y = t^2 * e^3 t + 6 and asked to determine the general solution to this equation. we convert the equation into r^2 + 9 = 0. The solution to this equation is r = +/- 3i. This solution converted to trigonometric function is equivalent to y= C1 cos3t + C2 sin3t.
