admin百科知識 2022-02-13 18:35:19 tan(π4-α)=-13 則sin(2α+π4)的值爲?tan(π/4-α)=-1/3 則sin(2α π/4)的值爲?網友廻答：匿名網友∵tan(¼π-α)=(1-tanα)/(1 tanα)=-1/3,∴tanα=2,∴sin2α=2tanα/(1 tan²α)=4/5,cos2α=(1-tan²α)/(1 tan²α)=-3/5,∴sin(2α ¼π)=½√2(sin2α cos2α)=√2/10. db標簽 生活常識_百科知識_各類知識大全»tan(π4-α)=-13 則sin(2α+π4)的值爲?
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