cos23度乘cos37度减 cos67度乘 cos53度等于多少?

2025-04-14 22:14:36
推荐回答(1个)
回答1:

cos23°cos37°-cos67°cos53°
=cos23°cos37°-sin23°sin37°
=cos(23°+37°)
=cos60°
=1/2