化简sin(a- π /6)^2+sin(a+ π /6)^2-sina^2

化简:sin(-a)cos(2π+a)sin(-a-π) 化简sin(2π+a) 化简；sin^2 A+sin^2(A-π/3)+sin^2(A+π/3) 化简sin^2A+sin^(A-π/3)+sin(A+π/3) sin^2(a-π/6)+sin^2(a+π/6)-sin^2a 化简 sin^2a+cosacos(π/3+a)-sin^2(π/6-a)帮个小忙啊. sin^2(-a)化简 化简sin(a- π /6)^2+sin(a+ π /6)^2-sina^2 sin²（a+π)cos(π+a)sin(-a-2π)/sin(π-a)cos³(-a-π) 化简 化简sin(2π-a)sin(π+a)coa(-π-a)除以sin(3π-a)cos(π-a) 化简 sin(2π-a)sin(π+a)cos-π-a) / sin(3π-a)cos(π-a) 化简:tan(2π-a)sin(-2π-a)cos(6π-a)/cos(a-π)sin(5π-a) 化简sin^2(α-π/6)+sin^2(α+π/6)-sin^2α [sin(a-6π)cos(7π/2-a)]/[sin(3π+a)+sin(a-π）】= 化简sin^(a-30°)+sin^(a+30°)-sin^a化简sin^2(a-30°)+sin^2(a+30°)-sin^2a sin（-19π/6）=?已知[3Sin(π+a)+Cos(π-a)]/4Sin(-a)-Sin(5π/2+a)=2，求tan a Sin(π+2a)/(1+cos2a) 化简. 化简Sin A + Sin 2A / 1+cos A +