sin²40°+sin²50°+2-tan135°怎么算=
sin²40°+sin²50°+2-tan135°怎么算=
高一数学三角比的求值题 sin^2 120°+cos90°+tan135°-cos^2(-330°)+sin(-240°
sin²1°+sin²2°+sin²89°+sin²88°=
计算:sin²1°+sin²2°+sin²3°...+sin²45°+sin
数列求和 sin²1°+sin²2°+sin²3°+.+sin²88°+sin&
sin²60° 怎么算
sin²1°+sin²2°+……sin²88°+sin²89°
sin²60°+cos²60°-根号2cos45°跪求,sin²乘以x怎么算
sin²70°怎么化简
证明sin(a+b)sin(a-b)=sin²a-sin² b,并用该式计算sin²20°
求下列三角函数值sin(-60度)+cos225度+tan135度=-----------------
求sin²20°+sin80°sin40°,并且要用sin(α+β)sin(α-β)=sin²α-s