# Math Help - Integrating trig functions

1. ## Integrating trig functions

This question is more about my understanding than solving. I've done the question asking me to show that the differential of cotx is -cosec^2x by putting it in the form cosx/sinx. Then the second part says "Hence find the exact value of the integral of cot^2x between pi/2 and pi/4". I don't really see how the first part helps with that.

From the basic Pythagorean identity: $\int_{\pi/4}^{\pi/2} \text{cot}^2 (x) \, dx = \int_{\pi/4}^{\pi/2} \text{cosec}^2 (x) - 1 \, dx$.
And from the previous answer you know what the integral of $\text{cosec}^2 (x)$ is ....