cos(π/4+X)=3/5,17π/12

COSX-SinX=3/5*2^0.5;cosX*sinX=7/50;CosX+sinX=-4/5*2^0.5,[sin2X+2(sinX)^2]/(1-tanX)=2[sinxcosx(cosx+sinx)]/cosx-sinx=-28/75