y=-2cos(x/2+π/3),x∈[28π/5,a),若该函数是单调函数,求实数a的最大值.

已知sinx=3/5,x∈(π/2,π),求【sin(x+y)+sin(x-y)】/【cos（x+y）+cos（x-y）】的值 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 y=2cos x (sin x+cos x) y =(cos^2) x - sin (3^x),求y' Sin x-sin y=2/3 cos x-cos y=1/2 求cos(x-y) 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) sin(x+y)cosx+cos(x+y)sinx=1/3 x∈(3π/2,2π) 求cos(2x+π/4) 化简y=sin^2(x)+2sin(x)cos(x)+3cos^2(x) 函数y=cos(3π/2-x)/cos(3π-x)最小正周期是 函数y=cos(3π/2-x)/cos(3π-x)最小正周期是： y=(sin x + COS x)^2 y=(cos x-2)/(cos x-1)的值域 求函数y=cos(x-π/3),x∈[-π/2,π/2]的值域, 函数y=cos(x+π/3)的值域(其中x∈[-π/2,π/3]) y=cos^2 x-cos x +1的值域y=cos^2 x+cos x +1的值域, 求值域y=2sinx+cos^2x,x∈[π/6,2π/3) y=2cos(2x+π/3)+1,x∈【0,π／2】的值域