Please make sure we can tell what the problem means; for example, is Sin2x supposed to be sin(2x) or sin^2(x)? And I have no idea what "n2y" means. An image of the actual problem would be a good idea.
- 1) Sin2x d2y/dx2=2y
- 2) a d2y/dx2= [1+(dy/dx)2]1/2
- 3) x2 d2y/dx2-(x2+2x)dy/dx+(x+2y)y=x2ex
- 4) d2y/dx2+2/x dy/dx=n2y