(sin20°×cos20°×cos40°×cos60°×cos80°)÷sin20°
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/10/06 22:55:57
(sin20°×cos20°×cos40°×cos60°×cos80°)÷sin20°
:(sin20°×cos20°×cos40°×cos60°×cos80°)÷sin20°
=1/2(2sin20°×cos20°×cos40°×cos60°×cos80°)÷sin20°
=1/2(sin40°×cos40°×cos60°×cos80°)÷sin20°
=1/4(2sin40°×cos40°×cos60°×cos80°)÷sin20°
=1/4(sin80°×cos60°×cos80°)÷sin20°
=1/8(2sin80°×cos80°×cos60°)÷sin20°
=1/8(sin160°×cos60°)÷sin20°
=1/8(sin20°×cos60°)÷sin20°
=1/8×cos60°
=1/8×1/2
=1/16
=1/2(2sin20°×cos20°×cos40°×cos60°×cos80°)÷sin20°
=1/2(sin40°×cos40°×cos60°×cos80°)÷sin20°
=1/4(2sin40°×cos40°×cos60°×cos80°)÷sin20°
=1/4(sin80°×cos60°×cos80°)÷sin20°
=1/8(2sin80°×cos80°×cos60°)÷sin20°
=1/8(sin160°×cos60°)÷sin20°
=1/8(sin20°×cos60°)÷sin20°
=1/8×cos60°
=1/8×1/2
=1/16
计算:(sin20°-sin40°)÷(cos20°-cos40°)
求值:cos20°sin20°
计算cos20°cos40°cos80°
1.(1—cos20° )除以(cos80° 乘sin20° )=根号二
1/cos20°-根号3/sin20°
化简((cos20°/sin20°)cos10°)+根号3(sin10°tan70°)-2cos40°
化简cos10°根号下1-cos40°/sin20°根号下1+cos20°
sin20°·cos40°+sin40°·cos20°怎么算
求值:(sin20°-sin40°)/cos20°-cos40°)
sin20°cos40°+cos20°sin40°的值等于( )
化简sin20°cos40°+cos20°sin40°=______.
计算:(sin20°-sin40°)÷(cos20°-cos40°),答案是-根号3,求详解!急急急急急!