Mệnh đề nào dưới đây sai? (3^x-e^-x)dx=3^x/ln3

A. $\int \left(3^x-{\text{e}}^{-x}\right)\text{\hspace{0.17em}d}x=\frac{3^x}{\ln 3}+{\text{e}}^{-x}+C$

B. $\int \frac{1}{{\cos }^{2}x}\text{\hspace{0.17em}d}x=\tan x+C$

C. $\int \frac{1}{x}\text{\hspace{0.17em}d}x=\ln x+C$

D. $\int \sin x\text{d}x=-\cos x+C$