-2pi/3

-2pi/3 化简间sin（a-2pi)cos(a+pi）tan(a-99pi)cos(pi-a)sin(3pi-a)sin（-a-pi） 下列区间中,是函数y=xcosx-sina的单调递增区间为A.(pi /2,3pi/2)B.(pi,2pi)C.(3pi/2,5pi /2)D.(2pi ,3pi) cos(Pi+a)=-0.5,3/2Pi sin(PI/2+a)=-4/5 a属于(Pi,3pi/2)则cos(Pi/3-a)为 化简sin(2x-pi)sin[x+(3/2)pi]/cos[x+(5/2)pi][1-sin(pi+x)] f(a)=sin(pi-a)cos(2pi-a)tan(-a+3pi/2)/cos(-pi-a) 求 f(-31pi/3)的值 tana=2求sin(pi-a)cos(2pi-a)sin(-a+3pi/2)/tan(-a-pi)sin(-pi-a) 化简(高一)[sin^2(pi+a)cos(pi+a)]/[tan(pi+a)cos^3(-pi-a)tan(2pi+a)] -Pi/2 化简：sin(2pi-a)sin(pi+a)cos(-pi-a)/sin(3pi-a)cos(pi-a)化简：sin(2pi-a)sin(pi+a)cos(-pi-a)---------------------------- sin(3pi-a)cos(pi-a)中间的一横是分数线 化简三角函数[sin(α+pi)*cos(pi+α)*cos(α+2pi)]/[tan(pi+α)*cos^3(-α-pi)][sin(α+pi)*cos(pi+α)*cos(α+2pi)]/[tan(pi+α)*cos^3(-α-pi)]算出来最后等于1 , cosa=2/3 a是第四象限角求sin(a-2Pi)+sin(-a-3Pi)cos(a-3Pi)/cos(Pi-a)-cos(-Pi-a)cos(a-4Pi) 化简sin(x+PI/3)+2sin(x-PI/3)-根号3*cos(2pi/3-1) 已知a∈(pi,3pi/2),cosa=-1/3,求sin(a-2pi/3)的值 已知cosa=3/5,且a属于(3pi/2,2pi),则cos(a-pi/3)= sin(pi/7)^2+sin(2pi/7)^2+sin(3pi/7)^2=怎么算 sin(pi/6-a)=1/3,则cos(2pi/3+2a)的值为pi是圆周率