化简:1/[cosa根号(1+sin^2a/cos^2a)]+2/[根号(1/sin^2a-1)tana]已知0

问题描述:

化简:1/[cosa根号(1+sin^2a/cos^2a)]+2/[根号(1/sin^2a-1)tana]
已知0

1+sin²a+/cos²a=(sin²a+cos²a)/cos²a=1/cos²a所以1/[cosa根号(1+sin^2a/cos^2a)]=1/(cosa*|1/cosa|)1/sin²a-1=(1-sin²a)/(sin²a)=(cosa/sina)²=cot²a所以2/...