化简:cos^4a-sin^4a/cos2a,求解这里的a是阿法

cos^4A-sin^4a 化简 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)== 化简 sin^4a-cos^4b 化简1-sin^4a-cos^4a/1-sin^6a-cos^6a 1-sin^6a-cos^6a分之1-sin^4a-cos^4a 化简 化简：sin^4a+cos^2a-sin^2a-cos^4a sin^4+sin^2cos^2+cos^2a= 化简：(sin^6a+cos^6a-1) / (sin^4ª+cos^4a-1) 化简1-cos^4a-sin^4a/1-cos^6-sin^6acos^6应为cos^6a 化简cos^2 a(2cos^2 a+3)-sin^2 a(2cos^2 a+3)-4sin^2 a cos^2 a +3 化简sin a+cos a Sin^4a-cos^4a= 4sin(a/4)cos(a/4)cos(a/2)cosacos2a化简,a是某角. 化简sin(A+π/4)sin(A-π/4)/sin^4A-cos^4A 化简：cos^4a-sin^4a= 化简sin^4a-cos^4a/cos2a 化简cos(π/4-a) / sin(π/4+a)