sin^6 a+cos^6 a+3sin^2 acos^2a=(sin^2 a+cos^2 a)(sin^4 a+cos^4 a-sin^2 acos^2 a)是如何计算出的

[Sin(6π+a)Cos(7π-a)]/[Sin(3π+a)+Sin(-π+a) sin^6 a＋cos^6 a＋3×sin^2 a×cos^2 a=? 由cos(a+b)=cos a cos b-sin a sin b cos(a-b)=cos a cos b+sin a sin b解题设a为锐角,证：1、2分之根3乘cos a + 2分之1乘sin a=cos(6分之π-a)2、cos a-sin a=根号2cos(4分之π+a) 已知(4sin a－2cos a)／(5cos a +3sin a)=6/11,求cos＾4 a－sin＾4 a (1-sin^6a-cos^6a)/(sin^2a-sin^4a) [sin(a-6π)cos(7π/2-a)]/[sin(3π+a)+sin(a-π）】= sin^6 a+cos^6 a+3sin^2 acos^2a=(sin^2 a+cos^2 a)(sin^4 a+cos^4 a-sin^2 acos^2 a)是如何计算出的 2(sin^6 α +cos^6α)-3(sin^4a+cos^4α)mingbaidian 2(sin^6 α +cos^6α)-3(sin^4a+cos^4α) sin^6a+cos^6a+3sin^2acos^2a的值为? 求证sin^6A+cos^6A=1-3sin^2Acos^A 求证 cos（A）+ 根号3sin(A)=2sin(π/6+A) sin平方a+cosa*cos(∏+a)/3-sin平方（∏-a)/6=? 根号3sin(π/6-a)-cos(π/6-a) 化简cos(π/3+a)+sin(π/6+a) 化简:cos(π/3+a)+sin(π/6)+a= 1-cos^6(a)-sin^6(a)化简得3sin^(a)cos^(a)的详细过程! 化简1-sin^4a-cos^4a/1-sin^6a-cos^6a