sin(兀-a)=5/4,acos(0,2/兀) 求sin2a-cos的平方2/a的值

sin(兀-a)=5/4,acos(0,2/兀) 求sin2a-cos的平方2/a的值 已知a(-0,兀且2SIN A-SIN ACOS A-3COS A=0求SIN(+兀/4)/SIN 2A+COS 2A+1的值 求证sin^4a+cos^4a=1-2sin^2acos^2a sin^4A+cos^2A+sin^2Acos^2A=? sin^4a-sin^2acos^2a+cos^2a=1 已知sin a+cos a= -1/5 求1）sin acos a 2）sin a-cos a 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 已知tan a =-4,求下列各式的值 (1)sin^2 a (2)3sin acos a (3)cos^2 a-sin^2 a (4)4sin a已知tan a =-4,求下列各式的值 (1)sin^2 a (2)3sin acos a (3)cos^2 a-sin^2 a (4) (4sin a-2cos a)/(5cos a+3sin a) a为任意角 已知tan a =-4,求下列各式的值 (1)sin^2 a (2)3sin acos a (3)cos^2 a-sin^2 a (4)4sin a已知tan a =-4,求下列各式的值 (1)sin^2 a (2)3sin acos a (3)cos^2 a-sin^2 a (4) (4sin a-2cos a)/(5cos a+3sin a) a为任意角 已知cos2a=（1/4),求cos^4a+sin^4+sin^2acos^2a的值 证明等式恒成立 sin^a+sin^b-sin^asin^b+cos^acos^b=1sin^a+sin^b-sin^asin^b+cos^acos^b=1 只需证sin^a(1-sin^b)+sin^b+cos^acos^b=1 只需证sin^acos^b+cos^acos^b+sin^b=1 这里到这里没有看懂 求证1+sin a+cos a+2sin acos a/1+sin a+cos a=sin a+cos a Sin^4a+cos^4a怎么=（sin^2a+cos^2a)-2sin^2acos^2a的.求详解.在线等 sin4次方a+sin²acos²a+2cos²a+sin²a= ? 已知函数f(x)=sin^2(x)+acos(x)+5/8(a)-3/2,x属于[0,π/2]的最大值为1,试确定a的 若sin A+cos A=1,则sin Acos A=? sin²a+cosˇ4a+sin²acos²a 化简 求证sin^6A+cos^6A=1-3sin^2Acos^A