Proof of the tangent angle sum and difference identities

[@KookyMiyuki]

There's a typo in the video description. The plus in the denominator should be a minus.
tan(x+y)=(tan(x)+tan(y))/(1-tan(x)tan(y))

[@Tharun-wk6rj]

it is so trivial leave it

[@jflanny]

So weird that you're still taking the time to make these. I'll do this for $40,000 annually.

[@dragonlovesdiamond9512]

It’s pointless if they get it wrong sometimes

[@robelnidaw8746]

It's so amazing. I love your content 😍

[@raysun1681]

Hi Khan Academy! I love your content!

[@craig7878]

There is a mistake, when you simplified the complex fraction, you canceled cos(y) leaving you with sin(x)+cos(x)sin(y)/cos(x). You then simplified the numerator sin(x) and denominator cos(x) into tangent. Leaving you with cos(x)sin(y)/cos(x), you then proceeded to simplify sin(y)/cos(y) into tangent - However the cos(y) had already been cancelled previously.. This is not the correct way to prove this identify. The entire thing should be multiplied by 1/cos(x)cos(y).

[@almoneez5739]

Craig you are incorrect. When you are simplifying the complex fraction cos(y) is not removed. The top of the complex fraction can be written as sin(x)cos(y) / cos(x)cos(y) + cos(x)sin(y) / cos(x)cos(y). Canceling the cos(y) in one term does not remove cos(y) in the denominator of the other.

[@MasterCivilEngineering]

Amazing 🇺🇸🇺🇸🇺🇸

[@JJ-uj1wi]

Thank you!

[@jacklawpants7944]

thanks sal khan

[@Maria-qv7qt]

Thanks

[@smallgiraffe3392]

Salman Khan,are you muslim?

[@tatetutor.]

Yes he is infact a muslim

[@anantav51]

@@tatetutor. you don't know that

[@rkusuma6852]

he used to, I guess. source from his Wikipedia page