sin^6a+cos^6a-2sin^4a-cos^4a+sin^2a=0

(1-sin^6a-cos^6a)/(sin^2a-sin^4a) 化简(1-sin^6 a-cos^6 a)/(cos^2 a-cos^4 a)== 已知(4sin a－2cos a)／(5cos a +3sin a)=6/11,求cos＾4 a－sin＾4 a (cos a)^4+(sin a)^2*(sin a)^2+(sin a)^2=? （1-sin^6a-cos^6a)/(1-sin^4a-cos^4a)=? 已知a(-0,兀且2SIN A-SIN ACOS A-3COS A=0求SIN(+兀/4)/SIN 2A+COS 2A+ 已知sin a-2cos a=0 求4sin^2 a-3sin a x cos a-5cos^2 a的值 若sin^4a/sin^2b+cos^4a/cos^2b=1,证明sin^4b/sin^2a+cos^4b/cos^2a 证明sin(4A)sin(2A)(1-cos(2A)) cos(4A)cos(2A)(1 cos(2A))=cos(2A 1-sin^6a-cos^6a分之1-sin^4a-cos^4a 化简 求值:1-sin^6a-cos^6a/1-sin^4a-cos^4a 化简1-sin^4a-cos^4a/1-sin^6a-cos^6a