Students sometimes have difficulty remembering the derivatives of sec(x), tan(x), csc(x), and cot(x). This video shows a fairly simple trick for making sure you always get these correct.
Amazing! I'm really happy I came across this video :D Edit: One thing I want to add , cause I don't think you mentioned it in the video, is that the chain rule still applies here. So: d/dx = [ sec(u)]= sec(u) tan(u) u'
