已知方程sin(α-3∏)=2cos(α-4∏),求[sin(∏-α)+5cos(2∏-α)]/[2sin(3∏/2-α)-sin(-α)]的值

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已知方程sin(α-3∏)=2cos(α-4∏),求[sin(∏-α)+5cos(2∏-α)]/[2sin(3∏/2-α)-sin(-α)]的值已知方程sin(α-3∏)=2cos(α-4∏),求[s

已知方程sin(α-3∏)=2cos(α-4∏),求[sin(∏-α)+5cos(2∏-α)]/[2sin(3∏/2-α)-sin(-α)]的值
已知方程sin(α-3∏)=2cos(α-4∏),求[sin(∏-α)+5cos(2∏-α)]/[2sin(3∏/2-α)-sin(-α)]的值

已知方程sin(α-3∏)=2cos(α-4∏),求[sin(∏-α)+5cos(2∏-α)]/[2sin(3∏/2-α)-sin(-α)]的值
sin(α-3∏)=2cos(α-4∏)
-sinα=2cosα
sinα=-2cosα

[sin(∏-α)+5cos(2∏-α)]/[2sin(3∏/2-α)-sin(-α)]
=(sinα+5cosα)/(-2cosα+sinα)
=(-2cosα+5cosα)/(-2cosα-2cosα)
=-3/4

变换,把原方程改改咯.