化简[sin(π/2+α)*cos(π/2-α)]/cos(π+α)+[sin(π-α)*cos(π/2+α)]/sin(π+α)
题目
化简[sin(π/2+α)*cos(π/2-α)]/cos(π+α)+[sin(π-α)*cos(π/2+α)]/sin(π+α)
答案
[sin(π/2+α)*cos(π/2-α)]/cos(π+α)+[sin(π-α)*cos(π/2+α)]/sin(π+α)
=cosαsinα/(-cosα)+sinα(-sinα)/(-sinα)
=-sinα+sinα
=0
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