已知sin(α-3π）=2cos(α-4π）,求sin(π-α）+5cos(2π-α） / 2cos(π-α)-sin(-α)的值?`

已知sin(α-3π)=2cos(α-4π),求[sin(π-α)+5cos(2π-α)]/[2cos(π-α)-sin(-α)] 的值 sin(α-3π)=2cos(α-4π) ===> sinα=-2cosα 则 [sin(π-α)+5cos(2π-α)]/[2cos(π-α)-sin(-α)] =(sinα+5cosα)/(-2...