sin17度*cos43度+sin73度*cos47度= 帮我把公式写出来?
问题描述：
sin17度*cos43度+sin73度*cos47度= 帮我把公式写出来?
答
sin17°·cos43°+ sin73°·cos47°
= sin17°·cos43°+ cos(90°-73°)·sin(90°-47°)
= sin17°·cos43°+ cos17°·sin43°
= sin(17°+ 43°)
= sin60°
= √3/2