+1 862 207 3288 differential equation
In Problems 19–22 solve each differential equation by variation of parameters, subject to the initial conditions y(0) = 1, y'(0) = 0.
19. 4y” – y = xex/2
20. 2y” + y’ – y = x + 1
21. y” + 2y’ – 8y = 2e–2x– e–x
22. y” – 4y’ + 4y = (12×2 – 6x)e2x
