(sin^2A+cos^2A)^3=sin^6A+cos^6A+3sin^2Acos^2A=1
又(sinA-cosA)^2=1-2sinAcosA=1/4 sinAcosA=3/8
sin^2Acos^2A=9/64
sin^6A+cos^6A=1-3*9/64=37/64
(sin^2A+cos^2A)^3=sin^6A+cos^6A+3sin^2Acos^2A=1
又(sinA-cosA)^2=1-2sinAcosA=1/4 sinAcosA=3/8
sin^2Acos^2A=9/64
sin^6A+cos^6A=1-3*9/64=37/64