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).
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.
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))
it is so trivial leave it
So weird that you're still taking the time to make these. I'll do this for $40,000 annually.
It’s pointless if they get it wrong sometimes
It's so amazing. I love your content 😍
Hi Khan Academy! I love your content!
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).
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.
Amazing 🇺🇸🇺🇸🇺🇸
Thank you!
thanks sal khan
Thanks
Salman Khan,are you muslim?
Yes he is infact a muslim
@@tatetutor. you don't know that
he used to, I guess. source from his Wikipedia page