6x=1-√x √x=1-6x x=36x^2-12x+1 36x^2-13x+1=0 (9x-1)(4x-1)=0 x=1/4,x=1/9 经检验x=1/4是增根 所以sina=1/9 cosa=±√[1-(sina)^2]=±4√5/9 tana=±√5/20 cos(a-5π)tan(2π-a)/cos(3π/2-a)cot(π-a) =cos(a-5...