1. The problem statement, all variables and given/known data What is the mass of a wire shaped like the arch x=t-sint, y=1-cost (t from 0 to 2*pi) of a cycloid C that has constant density D=k? 3. The attempt at a solution I must integrate D*ds. I find that ds=sqrt(2-2cost)dt. Is this wrong? If it's right, I don't know how to integrate k*sqrt(2-2cost).