4sin(a/4)cos(a/4)cos(a/2)cosacos2a化简,a是某角.

化简 1-sin^4a-cos^4a/cos^2a-cos^4a 化简(1-sin^6 a-cos^6 a)/(cos^2 a-cos^4 a)== 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 化简1-sin^4a-cos^4a/1-sin^6a-cos^6a 化简cos^4(a/2)-sin^4(a/2)= Sin^4a+Sina*Cosa+Cos^2a化简 化简 sin^4a-cos^4b 若sin^4a/sin^2b+cos^4a/cos^2b=1,证明sin^4b/sin^2a+cos^4b/cos^2a 化简 cot(a+4π)cos(a+π)[sin(a+3π)]^2/tan(π+a)[cos(-π-a)]^2 已知(4sin a－2cos a)／(5cos a +3sin a)=6/11,求cos＾4 a－sin＾4 a 已知sin a-2cos a=0 求4sin^2 a-3sin a x cos a-5cos^2 a的值