首页 > 留学知识库

问题: 高一三角函数!!

若图不清,可以点击放大。

解答:

∵ [(4n+1)π/4]-[(4n-1)π/4]=π/2, ∴ cos[(4n+1)π/4-α]=cos[π/2+((4n-1)π/4-α)]=-sin[(4n+1)π/4], ∴ 原式=sin[(4n+1)π/4]-sin[(4n+1)π/4]=0