请证明 secx^6-tanx^6=1+3tanx^2*secx^2
人气：255 ℃ 时间：2020-01-31 07:15:27
解答
secx^6-tanx^6=(sec^2-tan^2)(sec^4+sec^2tan^2+tan^4)=sec^4+sec^2tan^2+tan^4=sec^4-sec^2tan^2+tan^4-sec^2tan^2+3sec^2tan^2=sec^2(sec^2-tan^2)+tan^2(tan^2-sec^2)+3sec^2tan^2=sec^2 -tan^2+3sec^2tan^2=1+3t...
推荐
猜你喜欢
