求值,4-1/4sin^22a-sin^2a-cos^4a

求值,4-1/4sin^22a-sin^2a-cos^4a sin(-π/4)求值 求值：sin[1/2arctan(-4/3)] sin(-4分之π)求值 sin 11π/4 求值 1/4sin^2a+2/5cos^2a 求值tana=-2 求值：(1-sin^6 x-cos^6 x)/(1-sin^4 x-cos^4 x) 不用计算器,求值：cos【sin-1(4/5)】（注：sin的-1次方） 已知（tan a-3)(sin a+cos a+3)=0,求值:2/3sin²a+1/4cos²a 求值:1-sin^6a-cos^6a/1-sin^4a-cos^4a如题分子是/前的部分,分母是/后的部分 化简求值sin^4θ+sin^4(π/3-θ)+sin^4(π/3+θ) sin^4θ+sin^4(π/3-θ)+sin^4(π/3+θ)化简求值 求值:sin^4(∏/16)+sin^4( 3∏ /16)+sin^4( 5∏/16)+sin^4( 7∏/16) sin^a+cos^(π/6+a)+1/2sin(2a+π/6)求值 8sin(45+a)sin(45-a)=1,sin^4a-cos^4a= (1-sin^6a-cos^6a)/(sin^2a-sin^4a) cosA+cos^2A=1,sin^2A+sin^4A+sin^8A 求值sinA+sin(120+A)-sin(120-A)