1. The problem statement, all variables and given/known data Compute ∫f ds for f(x,y)= √(1+9xy), y=x^3 for 0≤x≤1 2. Relevant equations ∫f ds= ∫f(c(t))||c'(t)|| ||c'(t)|| is the magnitude of ∇c'(t) 3. The attempt at a solution So, with this equation y=x^3 ... I got the that c(t)= <t,t^3> c'(t)=<1,3t^2> I know that from the equation y=x^3... x=t=0 and 1... I don't know how to get the magnitude of such equation. They the lower and upper limit. Another thing is I cannot for the life of me figure out how to take the anti-derivative of √(1+9xy)... which by the time I change to t it would be √(1+9t^4)... Of course if I'm approaching this the wrong way please, tell me what I'm doing wrong. Please let me know if it isn't clear enough.