1. The problem statement, all variables and given/known data Integral of 6/(sqrt(4-x^2)) 2. Relevant equations arcsin(u) = u'/ sqrt(1-u^2) 3. The attempt at a solution WA gave a different answer http://www.wolframalpha.com/input/?i=Integral+of+6%2F%28sqrt%284-x^2%29%29 I got the following: Integral of 6/(sqrt(4-x^2)) divide by 4 to reduce to 1-u^2, and pull out the constant 4: 1/4 int of 6/sqrt(1-(x/2)^2 i was going to pull out the six right away, but i could integrate that with du. u = x/2, du = 1/2 dx, so 2 du = dx i get 12 inside, and pull out the 12, i get 12/4 int u' / sqrt(1-u^2) which gives me 3 arcsin(x/2)+c but this is not right from WA. Thank you.