d/dx integral from o to x of function cos(2*pi*x) du is

Question

first i do the integral and i find the derivative right.

by the fundamental theorem of calculus, if there is an integral from o to x, don't i just plug the x in the function.

the integral of the problem is cos*2*pi*) is just cos(2*pi*x) right or is that wrong. then i find the derivative.

<<the integral of the problem is cos*2*pi*x) is just cos(2*pi*x) right or is that wrong.>>
Wrong. The integral of that function is
[1(2 pi)]*sin(2*pi*x)