
则sinαcosα=-4/9 ∵α是三角形的一个内角 ∴α∈(0,π)

已知:cos(π α)=3/5,α为第三象限的角,求sinα,tanα的值

函数y=cos05πx的最小正周期是

梁荣业 v2|中小学教师 sinπ∕12cosπ∕12=(sinπ/6)/2=(1/2)÷2=1/4
图片内容是:cos4π
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原式=sinπ/6sinθcosπ/6cosθ =1/2sin2θ*1/2sin(π/3) =1/4sin2θ

已知函数fx=√2cos(x π/4),x∈r,求fx的最小正周期和值域,2,若⊙∈(0

cosπx的图像怎么画

已知cosα=-1/3,且α∈(π,3π/2),则sinα的值是?

=(cosbcosπ/4)-sinbsin π/4 =√2/2(cosb-sinb) =-√2/2(√2sinb-π