Look in a calculus book.
Umm to my knowledge… the derivative of 2cosx = -2sinx, however, when going for integral of 2cosx = 2sinx… because derivative of 2sinx = 2cosx… notice the sign doesnt change.
anti derivatives are integrals so
take out 2 and integrate cosx which is sin x
so answer is
Well, the antiderivative of cos x is sin x, so just multiply that by 2:
2 sin x
-2 sin (x)
**the anti derivative of cos is NOT sin, it’s – sin!**