sin(π/2+a)=3/5.则sin(π/2-6)

sin(π/2+a)=3/5.则sin(π/2-6) 若sin(π+α)+sin(-α)=-m,则sin（3π+a)+2sin(2π-a)的值为? 若函数sin(π/3+a)=2/3,则sin(π/6+2a)= 若sin(π-a)=2/3,则sin(2π-a)等于多少 已知sin(3π-a)=-2sin(π/2+a)则sinacosa等于 已知tana=2,则[sin(π/2+a)-cos(π-a)]/[sin(π/2-a)-sin(π-a)]=? [sin(a-6π)cos(7π/2-a)]/[sin(3π+a)+sin(a-π）】= 已知sin(3π-α)=-2sin(π/2+α)则sinαcosα 已知tana=2,则sin(π-a)cos(2π-a)sin(-a+3π/2)/tan(-a-π)sin(-π-a)= 3 在三角形ABC中,已知（a2+b2）sin（A-B）=（a2-b2）sin(A+B) 求证：ABC是等腰或直角三角形(a^2+b^2)sin(A-B)=(a^2-b^2)sin(A+B),(sin^A+sin^B)sin(A-B)=(sin^A-sin^B)sin(A+B) sin^A*(sin(A+B)-sin(A-B))=sin^B*(sin(A-B)+sin(A+B)) sin^A*2c sin（-19π/6）=?已知[3Sin(π+a)+Cos(π-a)]/4Sin(-a)-Sin(5π/2+a)=2，求tan a 化简sin(α+β)+sin(α-β)+2sinαsin(3π/2-β)= 已知sin(3π+a)=2sin(3π/2+a),sin^2a+sin2a = sin((3π)/3-a)=sin(π+(1/2-a))=-(sin(1/2-a))＝-cosa 已知sin(3π+a)=2sin[(3π/2)+a],求sin^2a+sin2a的值 sin a=0.4 则sin(π-a)=? 已知sin(a+π/4)+sin(a-π/4)=√2/3则sin(a-π/4)/1-cos2a-sin2a的值 化简求sin^2(a-π/3)+sin^2(a+π/3)+sin^2a