解方程：sin(2*a)/pi+(pi-a)/pi=0.8,最好能给出matlab程序.

化简：sin(2pi-a)sin(pi+a)cos(-pi-a)/sin(3pi-a)cos(pi-a) tana=2求sin(pi-a)cos(2pi-a)sin(-a+3pi/2)/tan(-a-pi)sin(-pi-a) f(a)=sin(pi-a)cos(2pi-a)tan(-a+3pi/2)/cos(-pi-a) 求 f(-31pi/3 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), cosa=2/3 a是第四象限角求sin(a-2Pi)+sin(-a-3Pi)cos(a-3Pi)/cos(Pi-a)- 化简间sin（a-2pi)cos(a+pi）tan(a-99pi)cos(pi-a)sin(3pi-a)sin（-a-p 三角形ABC中sin(2Pi-A)=－根号2cos(3Pi/2+B)根号3cos(2Pi-A)=根号2sin(Pi/2+ 已知a∈(pi,3pi/2),cosa=-1/3,求sin(a-2pi/3)的值 tanθ=a,求[sin(pi/4+θ)/sin(pi/2-θ)]*tan2θ tanθ=a,求[sin(pi/4+θ)/sin(pi/2-θ)]*tan2θ, 若cos(pi/6-a)=1/2,sin(a+pi/3)=?cos(2pi/3+2a)=?注:pi指圆周率 用matlab解方程：11169.66-5662.65*(sin(x-93*pi/180)+sin(93*pi/180-