设角=-35/6兀,则2sin(兀+a)cos(兀-a)-cos(兀+a)/1+sin^2a+sin(兀-a)-cos^2(兀+a)值=
A,/3/3 B.-/3/3 C./3 D.-/3快快点
人气：435 ℃ 时间：2020-03-20 09:27:11
解答
2sin(兀+a)cos(兀-a)-cos(兀+a)/1+sin^2a+sin(兀-a)-cos^2(兀+a)=2sina * cosa +cosa/1+sin^2a+sina-cos^2a=(2sina *+1)cosa /2sin^2a+sina=(2sina +1)cosa / (2sina+1)sina=cosa/sina=cota 注：sin^2a=(sina)^2...A,/3/3 B.-/3/3 C./3 D.-/3C
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