先化简,再求值.sin(2π-β)+tan(π-β)+cos（3π-β）,其中β=π/-6已知α=-4/3,0＜α＜π,求sinα和cosα已知直线经过点（0,-2）,且倾斜角的大小是60°,1.求直线l的方程2.求直线l与两坐标轴围成三角形的面积.

sin(-π/4)求值 sin(-7π／6)求值 sin(-4分之π)求值 求值sin(-17π/3) sin 11π/4 求值 求值sin(α+β)cosα-[sin(2α+β)+sinβ]/2 求值sin^2(α-π/6)+sin^2(α+π/6)-sin^2α cos^2(π/5)+sin^2(π/10) 求值 求值:sinθ=0.6,且π/2 求值:sin^2α+sin^2β-sin^2α×sin^2β+cos^2α×cos^2β Sin(π+π/6)Sin(2π+π/6)Sin(3π+π/6).Sin(2008π+π/6)求值 arccos(cos4)求值 sin(2arcsin1/3)求值 求值:2sinπ/6+sin3π/2-2cosπ+2sinπ/3 求值sin(π/2)*sin(π/3)+2cos(-π/2)-根号3*tan(π/3) sin^a+cos^(π/6+a)+1/2sin(2a+π/6)求值 求值sin²x+cos²(π/6+x)+1/2sin(2x+π/6) 求值【sin(2π-α)sin(π+α)cos(-π-α)】/【sin(3π-α)-cos(π-α)】 求值：sin(π/12)+cos(π/12)