Tìm nguyên hàm của hàm số $f(x)=\cos3x$.
![]() | $\displaystyle\displaystyle\int\cos3x\mathrm{d}x=\dfrac{1}{3}\sin3x+C$ |
![]() | $\displaystyle\displaystyle\int\cos3x\mathrm{d}x=\sin3x+C$ |
![]() | $\displaystyle\displaystyle\int\cos3x\mathrm{d}x=3\sin3x+C$ |
![]() | $\displaystyle\displaystyle\int\cos3x\mathrm{d}x=-\dfrac{1}{3}\sin3x+C$ |