f(x）=tan^2x求f'(x)f''(x)在0到π/4的微积分

Question

f(x）=tan^2x 求f'(x)f''(x)在0到π/4的微积分

Answer 1

先化简∫f'(x)f''(x)dx分步积分
∫f'(x)f''(x)dx=f'(x)f'(x)-∫f'(x)f''(x)dx所以∫f'(x)f''(x)dx=f'(x)f'(x)/2
然后对f(x）=tan^2x 求导带点入可得4