sinA=3sin(2π/3-A) SINA=?sinA=3sin(2π/3-A) SINA=?答案是-3√3cosA

1- sin(2π/3 - a)/sina sinA=3sin(2π/3-A) SINA=?sinA=3sin(2π/3-A) SINA=?答案是-3√3cosA 设锐角三角形ABC的三个内角为,a,b,c分别是内角A,B,C所对边长,并且sinA*sinA=sin（π/3+B）+sin（π/3-B）+sinB*sinB（1） 求角A的值（2） 若向量AB*向量AC=12,a=2√7,求b,c（其中b＜c）“sinA*sinA=sin（π/3+B）+si 在三角形ABC中,sinA-sinB/sin(A B)=√2sinA-si在三角形ABC中,sinA-sinB/sin(A B)=√2sinA-sinC/sinA sinB.(1)求B,(2)若cosA=3/5,求sinC的值 设(sina)^2-sina-2(cosa)^2=0,求sin(a-3π/2) 已知(sina+cosa)/(sina-cosa)=3 则2sin'a+(sina-cosa)'=? 证明sinA+sin(A+2π/3)+sin(A-2π/3)=0 证明sinA+sin(A+2π/3)+sin(A-2π/3)=0 若3sin²a+sin²β=2sina,求2sina+sin²β sinA+sin(120-A)=3/2 求A度数 sin(a+kπ)=2cos[a+(k+1)π].求5cosa+3sina/4sina-2cosa sin(a+kπ)=2cos[a+(k+1)π].求5cosa+3sina/4sina-2cosa sin(6/π-a)=1/3 sina= 已知sin(π+a)=1/3,则sina= sin(3π-a)=sina?三角函数诱导 已知3SIN^2A+2SIN^2B=5SINA,求SIN^2A+SIN^2B范围 已知sina=15/17,a∈(π/2,π),求sin(π/3+a),sin(π/3-a) 已知sina=15/17,a∈（π/2,π)求sin(π/3+a),sin(π/3-a)急