作业帮sin(18°)sin(54°)sin(18°)*sin(54°) 不用计算器
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sin(18°)sin(54°)sin(18°)*sin(54°) 不用计算器
sin(18°)sin(54°)
sin(18°)*sin(54°) 不用计算器
sin(18°)sin(54°)sin(18°)*sin(54°) 不用计算器
cos36*cos72
=cos36*sin18
=(1/cos18)*sin18*cos18*cos36
=(1/2cos18)*sin36*cos36
=(1/4cos18)*sin72
=1/4
sin(54°)=cos(36°)
原式=[sin(18°)*cos(36°)]/1 分母是1
=[cos(18°)*sin(18°)*cos(36°)]/cos(18°)
=[sin(36°)*cos(36°)]/[2cos(18°)]
=[sin(72°)]/[4cos(18°)]
=[cos(18°)]/[4cos(18°)]
=1/4
sin(18°)sin(54°)sin(18°)*sin(54°) 不用计算器
sin
sin
sin(10°)+sin(50°)-sin(70°) =sin(10°)+sin(50°)-sin(70°) =
sin 18°等于多少?
sin?°≈0.6773?
sin 15°是多少
sin²1°+sin²2°+sin²3°+.+sin²89
化简:sin^A*sin^A+sin(A-60°)*sin(A-60°)+sin(A+60°)*
计算:sin方10°+sin方20°+sin方30°+sin方40°+sin方50°+sin方60°+sin方70°+sin方80°+sin方90°=
计算：sin²1°+sin²2°+sin²3°...+sin²45°+sin²46°...+sin²89°
计算：sin²1°+sin²2°+sin²3°+...+sin²87°+sin²88°+sin²89°
求sin²10°+sin²20°+sin²40°+sin²50°+sin²70°+sin²80°
sin²1°+sin²2°+sin²3°+……+sin²87°+sin²88°+sin²89°=
sin²1°+sin²2°+sin²3°+...+sin²88°+sin²89°+sin²90°=等于多少?
化简sin^(a-30°)+sin^(a+30°)-sin^a化简sin^2(a-30°)+sin^2(a+30°)-sin^2a
sin sin 为什么?sin 为什么?
比较大小(1)sin(-π/11)与sin(-π/17) (2)-sin(54π/7)与sin(-63π/8) (3)sin231°与cos260°