(tan22.5`)/(1-tan22.5`*22.5`)+(tan150`)/(1-tan150`*tan150`)
问题描述:
(tan22.5`)/(1-tan22.5`*22.5`)+(tan150`)/(1-tan150`*tan150`)
答
=0.5*((2tan22.5`)/(1-tan22.5`*22.5`))+0.5((2tan150`)/(1-tan150`*tan150`)){倍角公式}
=0.5*(tan45+tan300)
=0.5*(1-tan60)