sin(18°)sin(54°)

计算：sin²1°+sin²2°+sin²3°...+sin²45°+sin&# 数列求和 sin²1°+sin²2°+sin²3°+.+sin²88°+sin& 求解三角函数方程8sin^3 18°-4sin 18° +1=0 证明：(1) sin(360°-α)=-sinα 一道数学化简题sin 90°-α/sin α ＝ 证明：sin(360°-α)=-sinα sin(a+360°)=? sin²1°+sin²2°+sin²89°+sin²88°= sin²1°+sin²2°+……sin²88°+sin²89° sin^2 (0°)+sin^2( 1°)+.+sin^2(90du) 求和 证明sin(a+b)sin(a-b)=sin²a-sin² b,并用该式计算sin²20° 计算:sin方10°+sin方20°+sin方30°+sin方40°+sin方50°+sin方60°+sin方70°+s