18-27 IVP S, SOME WITH DISCONTINUOUS . INPUT 18. 9y" - 6y +y = 0,K0) = 3. v'(O) = 1 19. y" + 6y' + 8y = e-3t - e-5t

= y(0) , y'(0) = 0 20. y" + 10y + 24y = 14412, (0) = 19/12.y (0) = -5%3D 21. y" +9y 8 sin t if 0 T:(0) = 0, y'(0) = 4 22. y" + 3y + 2y 4t if 0 %3;M0) = 0, y'(0) = 0 23. y" + y' - 2y 3 sin t- cos t if 0 27; y(0) = 1, y (0) = 03334 24. y" + 3y' + 2y = 1 if 0 1;(0) = 0, y'(0) = 0 25. y" + y tif 0 1; y(0) = 0,y (0) = 0 26. Shifted data. y" + 2y + 5y 10 sin tif 0 27; y(T) = 1, y'(T) = 2e- 2 7. Shifted data. y" + 4y 812 if 0 5; y(1) = 1+ cos 2, y'(1) = 4 - 2 sin 2