Question

化简下列各式。

（1）8sinπ/48·cosπ/48·cosπ/24·cosπ/12；
（2）cos36°·cos72°.
请写清解题步骤。

Answer 1

1. 8sinπ/48·cosπ/48=8*1/2sinπ/24, sinπ/24cosπ/24=1/2sinπ/12,
sinπ/12cosπ/12=1/2sinπ/6, 所以原式=
8*1/2*1/2*1/2sinπ/6=sinπ/6

追问

谢谢