start by estimating the integral by a riemann sum. it all depends on knowing what dot products measure. (hint: the more parallel two vectors are, the greater their dot product.)
2a/b are both answers are equal to zero. I used the potential function out that f=xy and apply the f(Q)-f(P) which ends up with zero answer. But I need to find the answer using different formulas. SO, can anyone shows me other formulas