F(x, y) = (8xy3+9)i + (12x²y² + 2e2)j is conservative by finding a potential function f for F, and use f to compute ate S F. dr, where C is the curve given b 2t r(t) 2 sin ti+sin 5tj 4 for 0≤t≤π/2. f(x,y) = F-dr=