化简1/1+tanα -1/1-tanα 的结果是

问题描述:

化简1/1+tanα -1/1-tanα 的结果是

1/(1+tanα)-1/(1-tanα)
=[(1+tanα)-(1-tanα)]/[(1+tanα)(1-tanα)]
=2tanα/[1-(tanα)^2]
=tan2α.