y=2cos(2x+π/3)+1 =2cos2xcosπ/3-2sin2xsinπ/3+1 =cos2x-√3sin2 接下去怎么化简

y=cos(π/3-x)cos[π/2（x-1)]判断奇偶性y=cos(π/3-x)cos(π/3+x)判断奇偶性 Sin x-sin y=2/3 cos x-cos y=1/2 求cos(x-y) y=(cos x-2)/(cos x-1)的值域 y=cos^2 x-cos x +1的值域y=cos^2 x+cos x +1的值域, 【高中数学】已知cos(x+y)=1/3,cos(x-y)=2/3,且0 已知cos(x+y)=1/3,cos(x-y)+2/3,且0 2cos(A-B)+2cos（B-C)+2cos（C-A）=-3 求cos（2A-2C）由判别式得：cos[(x-y)/2]>=1 没看懂~ 证明COS（X+Y）COS（X-Y）=COS^2X-SIN^2Y 证明cos(x+y)cos(x-y)= cos^2(x)-sin^2(y) y=2cos x (sin x+cos x) 函数Y=cos 2x 的图象平移向量(- π/6 1/2)后.新位置图象对应的函数y=?A 1/2+cos(2x- π/3) B 1/2+cos(2x+π/3) c cos(2x+π/3)-1/2 D cos(2x+π/6)+1/2 函数y=(cos x+sin x)/(cos x-sin x)的最小正周期是多少?A.1 B π/2 C 2π D π 证明cos 2x cos x=1/2(cos x+cos 3x) y =(cos^2) x - sin (3^x),求y' 函数y=cosπ/2x×cosπ/2(x-1)的最小正周期 函数y=cosπ/2x×cosπ/2(x-1)的最小正周期 y=cos【πx/2】cos【π(x-1)/2】的周期 cos(x-y/2)=-1/9,sin(x/2-y)=2/3,π/2