证明:1/tana +sina/1+cosa =1/sina

问题描述:

证明:1/tana +sina/1+cosa =1/sina
(1) / (tana) + (sina) /(1+cosa) = (1) /(sina)

(sinα)^2=1-(cosα)^2==>(sinα)^2=(1+cosα)(1-cosα)==>sinα/(1+cos)=(1-cosα)/sinα,
∴cosα/sinα+(1-cosα)/sinα=1/sinα=右边,