sin7/3pi×cos（-11/6pi）+tan（-15/4pi）求值

化简间sin（a-2pi)cos(a+pi）tan(a-99pi)cos(pi-a)sin(3pi-a)sin（-a-p sin^3（-a）cos（2pi+a）tan（-a-pi）化简 化简三角函数[sin(α+pi)*cos(pi+α)*cos(α+2pi)]/[tan(pi+α)*cos^3(-α-p 已知函数f（x）=cos（2x-pi/3）+2sin（x-pi)*sin(x+pi/4) a,b∈（3pi/4,pi）,sin(a+b)=-3/5,sin(b-pi/4)=12/13,则cos（a+pi/4）= 是否存在a属于（-pi/2,pi/2）,b属于（0,pi),使等式sin（3Pi-a)=根号2cos(pi/2)-b), cos（α-pi/6）+sinα=(4/5) √3,则sin（α+pi/6）=? f(a)=sin(pi-a)cos(2pi-a)tan(-a+3pi/2)/cos(-pi-a) 求 f(-31pi/3 （全题）已知sin(α+3pi/4)=5/13,cos(pi/4-β)=3/5,且-4/pi小于α小于pi/4,pi/4 pi tana=2求sin(pi-a)cos(2pi-a)sin(-a+3pi/2)/tan(-a-pi)sin(-pi-a) cos(-pi/3)=?