已知sinA=-2cosA,则sin^2+5sinAcosA+2cos^2A=
已知sina+cosa=0,求sin^2a+2sinacosa+cos^2a
已知sina+cosa=根号2,求sinacosa,tana,sin^4a+cos^4a
已知sina+cosa=1/2,求sinacosa和sin^3a+cos^3a
tana=2 5-2sinacosa=?(sina+cos^3a)/cosa+sin^3a=?
已知tan=-4,求sin方a,3sinacosa,cos方a-sin方a,4sina-2cosa/5cosa+3sin
tana=2,求2sina+cosa/sina-cosa和sin^2a-2Sinacosa+3cos^2a
已知tana=3,计算 1、4sina-2cosa/5cosa+3sina 2、sinacosa 3、(sina+cos
若sina+cosa=1/2则sinacosa=?sina+cosa=1/2 两边平方sin^2a+cos^2a+2si
已知a是三角形内角,sina+cosa=1/4,求sin^2a+3sinacosa+5cos^2a的值.
sina+cosa/sina-cosa=2 求sin^2a-2sinacosa+1
已知sin a+cos a=1/2 sina*cosa=?cos a/sina+sina/cosa=?
已知tana=-1/3,计算 1)sina+2cosa/5cosa-sina 2)1/2sinacosa+cos*2a