int {pi/4}^{pi/2} \ csc^{2}x dx im so lost when trying to do this problem. i know that csc is 1/sin. i've tried using the half-angle identity but it didnt work. can someone explain.
Follow Math Help Forum on Facebook and Google+
Originally Posted by viet int {pi/4}^{pi/2} \ csc^{2}x dx im so lost when trying to do this problem. i know that csc is 1/sin. i've tried using the half-angle identity but it didnt work. can someone explain. You are making it too complicated. First, INT sec^2 x dx = tan x+C That is a well known integral. Similarly, INT csc^2 x dx = -cot x+C (Just note the negative, because like with sine and cosine the signs change when you look at them).
so now do i evaluate pi/4 to pi/2 for -cot(x)?
Originally Posted by viet so now do i evaluate pi/4 to pi/2 for -cot(x)? Yes. Integral evaluted at upper limit minus the lower limit.
View Tag Cloud