cos20°-cos40°-cos80°=

来源：学生作业帮助网 编辑：作业帮 时间：2024/04/29 08:40:02
cos20°-cos40°-cos80°=

cos20°-cos40°-cos80°=
cos20°-cos40°-cos80°=

cos20°-cos40°-cos80°=
cos40+cos80
=cos(60-20)+cos60+20)
=cos60cos20+sin60sin20+cos60cos20-sin60sin20
=2cos60cos20
=2*1/2*cos20
=cos20
cos20-cos40-cos80=cos20-cos20=0

0

cos20-(cos40+cos80)
=cos20-[cos(60-20)+cos(60+20)]
=cos20-[(cos60c0s20+sin60sin20)+(cos60cos20-sin60sin20)]
=cos20-2cos60cos20
=cos20-2*1/2*cos20
=cos20-cos20
=0

cos20°-cos40°-cos80°= cos20°cos40°cos80°=? 计算cos20°cos40°cos80° 化简cos20°cos40°cos60°cos80° cos20°*cos40°*cos60°*cos80°= cos20°cos40°cos60°cos80°是多少 不查表求:cos20°*cos40°*cos60°*cos80°= 化简cos20°-cos40°-cos80°等于? cos20°cos40°cos80°怎么算 cos20°cos40°cos80°的值、急 cos20°-cos40°-cos80°的值为? cos20°cos40°cos80°的值是 计算cos20°cos40°cos80°=多少 cos20°×cos40°×cos80°=______ cos20°+cos40°+cos80°=______ (sin20°×cos20°×cos40°×cos60°×cos80°)÷sin20° 求cos20°cos40°cos80°sin10°sin50°sin70° 化简求值：cos10°*cos20°*cos40°*cos80°*cos160°