1. The problem statement, all variables and given/known data integral of 1/sqrt(9-x^2) from 0 to 3 2. Relevant equations /// 3. The attempt at a solution I integrate it correct to arcsin(x/3) from 0 to 3 Get the correct anwser of pi/2. But there is another question, At which value of x in the integration region [0,3] does special care need to be taken with the integration? I understand at some point it goes from negatie to positive, but i tried 0,3,pi/2,pi.. none worked.. anyhelp?