вот попробовал =>
int(0,1){-x dx + y dy} = int(0.1){ -x dx + 3*sqrt(1-x^2) dy} = int(0.1){ -x dx + 3*sqrt(1-x^2) * (-3x/sqrt(1-x^2) ) dx} = int(0.1) {-x dx - 9x dx} = int(0.1){-10xdx) = -10
верно?