已知sin(a+π/4)=1/3,且π/2
问题描述:
已知sin(a+π/4)=1/3,且π/2
数学人气:248 ℃时间:2020-04-15 07:47:36
优质解答
cos(3π/4-a)
=cos(a-3π/4)
sin(a+π/4)
=sin(a+π-3π/4)
=-sin(a-3π/4).诱导公式
=1/3
∵π/2
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答
cos(3π/4-a)
=cos(a-3π/4)
sin(a+π/4)
=sin(a+π-3π/4)
=-sin(a-3π/4).诱导公式
=1/3
∵π/2