1. The problem statement, all variables and given/known data Consider the points P(1,0) and Q(0,1) on the unit circle. For which point R(cos(theta),sin(theta)) on the unit circle, is the area of the triangle PQR maximal? 2. Relevant equations Hint - It might be easier to use vectors to calculate the area of the triangle. 3. The attempt at a solution I'm really not sure how to approach this question. It's part of an integration question set. A wild guess would assume cos(pi/4) and sin(pi/4) would be the co-ordinates that would give a maximal area but I'm not sure if that's right or how to prove it. Thanks for any help.