设tan(5π+α)=m,则sin(α-3π)+cos(π-α)sin(-α)-cos(π+α)的值为()A.m-1m+1B.-1C.m+1m-1D.1-数学

题目简介

设tan(5π+α)=m,则sin(α-3π)+cos(π-α)sin(-α)-cos(π+α)的值为()A.m-1m+1B.-1C.m+1m-1D.1-数学

题目详情

设tan(5π+α)=m,则
sin(α-3π)+cos(π-α)
sin(-α)-cos(π+α)
的值为(  )
A.
m-1
m+1
B.-1C.
m+1
m-1
D.1
题型:单选题难度:中档来源:不详

答案

∵tan(5π+α)=m,
∴tanα=m,
sin(α-3π)+cos(π-α)
sin(-α)-cos(π+α)

=class="stub"-sinα-cosα
-sinα+cosα

=class="stub"tanα+1
tanα-1

=class="stub"m+1
m-1

故选C.

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