PART 9：例題:-積化和差(求不定積分)

\(\int {\sin 5x\cos 3x\;dx} \)

SOL：

(利用積化和差拆開)

\(\int {\sin 5x\cos 3x\;dx} \)

\( = \frac{1}{2}\int {(\sin 8x + \sin 2x)\;dx} \)

\( = \frac{1}{2}\left[ { - \frac{1}{8}\cos 8x - \frac{1}{2}\cos 2x} \right] + C\)