问题补充说明：cos2x等于什么??
cos2X=(cosX)^2-(sinX)^2
=2*(cosX)^2-1
=1-2*重充见还止先其针(sinX)^2
cos2x等于什么??
jacky
2024-01-23 10:38
阅读 433
jacky
2024-01-23 10:38
阅读 433
