Question

求证:Sin^2 x / (sinx-cosx) - (sin x + cos x)/(ta

Answer 1

原式=sin^2 x/(sinx-cosx)-(sinx+cosx)/(sin^2 x/cos^2 x-1)=sin^2 x/(sinx-cosx)-(sinx+cosx)*cos^2 x/(sin^2 x-cos^2 x)=(sin^2 x-cos^2 x)/(sinx-cosx)=sinx+cosx