若I=∫0xt3f(t2)dtI = \int_{0}^{x} t^3 f(t^2)dtI=∫0xt3f(t2)dt,则( ).
(A)I=∫0exxf(x)dxI = \int_{0}^{e^x} x f(x)dxI=∫0exxf(x)dx
(B)I=∫0xxf(x)dxI = \int_{0}^{x} x f(x)dxI=∫0xxf(x)dx
(C)I=12∫0xxf(x)dxI = \dfrac{1}{2}\int_{0}^{x} x f(x)dxI=21∫0xxf(x)dx
(D)I=12∫0x2xf(x)dxI = \dfrac{1}{2}\int_{0}^{x^2} x f(x)dxI=21∫0x2xf(x)dx
Copyright ©