积分积错了````````````记积分f(x)在下限为 a 上限为b 为∫ [a,b] f(x)dx不是乘法`````````不是∫∫（x^2+y^2）dxdy∫[-h,h]z^2 dz而是∫∫dxdy∫ [-h,h] (x^2+y^2+z^2) dz∫∫dxdy∫...