求证:1+2sina cosa /sin^2a -cos^2a = tana +1/tana -1.

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/17 16:30:49
求证:1+2sina cosa /sin^2a -cos^2a = tana +1/tana -1.
x){{fjg%*$'*qF @U(Iii]C="}5Ph˞07:QS_ziC哞yhƹ@lhna Ԡa,h/j@4+w#p(ЕŒBhfB%ozF 1Wź$

求证:1+2sina cosa /sin^2a -cos^2a = tana +1/tana -1.
求证:1+2sina cosa /sin^2a -cos^2a = tana +1/tana -1.

求证:1+2sina cosa /sin^2a -cos^2a = tana +1/tana -1.
左式=(1+sin2α)/(-cos2α)(倍角公式)
=(1+2tanα/(1+tan²α))/-(1-tan²α)/(1+tan²α))(万能公式)
=((1+tan²α+2tanα)/-(1+tan²α))/(1-tan²α)/(1+tan²α))
=(1+tanα)²/-(1-tan²α)
=(1+tanα)²/-((1-tanα)(1+tanα))
=(1+tanα)/-(1-tanα)
=(tanα+1)/(tanα-1)
=右式