$sinx / cos^3x * dx Checking the operator

[Riazy]

Hello, guys, here is my solution to the integral. I have a problem though, I get minus instead of plus, and would like some of u to check it out.
And if you have some alternative ways to solve it, please present them.

Image:

 

[tkhunny]

\(\displaystyle \frac{d}{dx}\sin(x) = \cos(x)\)

\(\displaystyle \frac{d}{dx}\cos(x) = -\sin(x)\)

Note that "minus" in that second one.