[（sin x-cos x）/(sin x+cos x)]^4 求定积分 积分区间0-π/4

题目

[（sin x-cos x）/(sin x+cos x)]^4 求定积分 积分区间0-π/4

答案

[（sin x-cos x）/(sin x+cos x)]^4 =[(1-tgx)/(1+tgx)]^4=[tg(x-45)}^4=[sec^2(x-45)-1]^2
由此再求,上面两答案都不对