∫ cost/(sint + cost) dt= (1/2)∫ [(cost + sint) + (cost - sint)]/(sint + cost) dt= (1/2)∫ [1 + (cost - sint)/(sint + cost)] dt= t/2 + (1/2)ln|sint + cost| + C设ƒ(t) = cost/(sint + cost) ∫(0→...