Open fadfadfafsfasd opened 5 years ago
https://purethought.cn/2019/10/16/%E7%BC%96%E7%A8%8B/C/%E4%B8%89%E7%82%B9%E6%B1%82%E8%A7%92/
利用向量公式：AB·AC=|AB|·|AC|·cos（theta）
int main()
{
//90,45,45 //double
https://purethought.cn/2019/10/16/%E7%BC%96%E7%A8%8B/C/%E4%B8%89%E7%82%B9%E6%B1%82%E8%A7%92/
利用向量公式：AB·AC=|AB|·|AC|·cos（theta）
include<iostream>
include<cmath>
int main()
{