F(x)=∫√(4-x^2)dx=2∫√[1-(x/2)^2]dx |x/2|≤1,令sint=x/2,则x=2sint F(x)=2∫√(1-sint^2)d(2sint)=4∫cost^2dt =4∫costd(sint)=4costsint-4∫sintd(cost)=4costsint+4∫sint^2dt =4costsint+4∫(1-cost^2)dt=4...