sin(45+2x)sin(45-2x)=1/4 是怎么化成 sin(45+2x)cos(45+2x)
Sin^x怎么变化成 1-cos(2x) /2
已知tan=2,求(cos x+sin x)/(cos x-sin x)+sin^2x
求证(cos^2 x-sin^2 x)(cos^4 x+sin^4 x)+1/4 sin 2x sin 4x=cos 2
化简[1-(sin^4x-sin^2cos^2x+cos^4x)/(sin^2)]+3sin^2x
(1-(sin^4x-sin^2xcos^2x+cos^4x)/sin^2x +3sin^2x
(sin^2x+cos^2x )(sin^2x-cos^2x)怎么得sin^2x-cos^2x?
sin^2x+cos^2x)(sin^4x-sin^2xcos^2x+cos^4x) =sin^4x-sin^2xcos
证明sin^2(x)+cos^2(x+30)+sin(x)cos(x+30)=3/4
lim(sin(x^2*cos(1/x)))/x怎么做?
三角等式求证:cos^6x+sin^6x=1-3sin^2x+3sin^4x
函数Y=3sin^2 x -2根号3sin x cos x +5cos^2 X 在 《0,45》上的值域是
化简 cos^2(x)*sin^2(x)-sin^2(x)