sin(a+pi/3)=1/4 求a
tana=2求sin(pi-a)cos(2pi-a)sin(-a+3pi/2)/tan(-a-pi)sin(-pi-a)
已知a∈(pi,3pi/2),cosa=-1/3,求sin(a-2pi/3)的值
f(a)=sin(pi-a)cos(2pi-a)tan(-a+3pi/2)/cos(-pi-a) 求 f(-31pi/3
cosa=2/3 a是第四象限角求sin(a-2Pi)+sin(-a-3Pi)cos(a-3Pi)/cos(Pi-a)-
tanθ=a,求[sin(pi/4+θ)/sin(pi/2-θ)]*tan2θ
tanθ=a,求[sin(pi/4+θ)/sin(pi/2-θ)]*tan2θ,
a,b∈(3pi/4,pi),sin(a+b)=-3/5,sin(b-pi/4)=12/13,则cos(a+pi/4)=
已知a,b,属于(3pi/4,pi),sin(a+b)=-3/5,sin(b-pi/4)=12/13,则cos(a+pi
sin(a+b)=-1/3cosb=2根号6/5,a属于(3PI/2,2PI) b属于(0,PI/2)求cosa
已知a锐角 且sin(a-pi/6 )=1/3 求sina
化简:sin(2pi-a)sin(pi+a)cos(-pi-a)/sin(3pi-a)cos(pi-a)
sin(pi/6+a)=1/3 则cos(pi/3-a)是多少