Question

三角函数的教学视频有吗?

Answer 1

http://you.video.sina.com.cn/b/19269232-86861592.html

http://v.youku.com/v_show/id_XNjM2MzcwNjQ=.html

http://v.ku6.com/show/nwqAdo-yEnDS8aiB.html