Question

Integral of (cos x/ sin x) from pi/4 to pi/2

Answer 1

\[\int\limits_{\pi/4}^{\pi/2} (\cos x / \sin x)\]

Answer 2

What is the antiderivative of cotanget?

Answer 3

u - sub for this one. try
\[u=\sin(x), du=-\cos(x)dx,-du=\cos(x)dx\] and you are just about done

Answer 4

Satellite73 is on a better track, follow that advice.

Answer 5

so the answer is -ln abs value of sin x

Answer 6

and while you are at it, might as well make
\[u(\frac{\pi}{4})=\frac{\sqrt{2}}{2}\]
\[u(\frac{\pi}{2})=1\] so you don't have to change back when you integrate

Answer 7

get
\[-\int_{\frac{\sqrt{2}}{2}}^1\frac{du}{u}\]

Answer 8

i thought that was that after u integrate du/u you get -ln sinx and then u evaluate that at both pi/4 - pi/2