• Wow, if I left the answer at 2/root (5), I would have had partial credit. My teacher went through a lot of﻿ trouble rationalizing radicals. Never leave radicals in the denominator. He wanted everything simplified, I guess I am stuck that way myself.

• It is important that trigonometry students know how to rationalize the denominator. But I don't have them do it all the time. It was more important when there were no calculators because getting a decimal approximation to an answer, by hand, is much easier if the denominator﻿ is a whole number.

• theres 2 kinds of math:

1. memorizing: this is the kind of math that most people think about, and it is a highly perishable skill. usually this kind of math is performed by people who only want to know enough math to pass a test. learning math like this is usually not useful for anything that isn't an exam.

2. understanding: people who solve math problems so that they can understand them usually don't have to rely on memorizing formulas, since they can﻿ probably derive whatever they need.

• wow.. i feel like i just learned.. two weeks worth of math that my really bad teacher tried to teach us..

you are amazing!﻿

• textbooks are pieces of shit when it comes to﻿ learning, this guy made it make more sense

• Man... I wish this guy was my trig instructor. That is the first time in weeks I've heard these formulas explained in﻿ a manner that makes sense.

• I have an amazing﻿ precalc teacher! I just need more practice is all.

• Thanks : )﻿

• thx ﻿

• why is he multiplying radical 8/5 by 1/2 in the first﻿ example?

• My professor started teaching this, Though i'm still having difficulty﻿ with this... I guess I get confused as to where anything goes in terms of Sin, And Cos,etc. I think maybe i'm just confusing myself by trying to mix it with Algebra. Wouldn't it be almost similar to algebra though? Thanks

• good﻿ video

• You make it look easy. Thank youuu. <3﻿