Eccentricity and directrix of the conic section (KristaKingMath)

Learn how to use the polar equation of a conic section to identify the conic as a parabola, an ellipse, or a hyperbola, find eccentricity and the equation of the directrix, and the sketch the conic.

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Hi, I’m Krista! I make math courses to keep you from banging your head against the wall. ;)

Math class was always so frustrating for me. I’d go to a class, spend hours on homework, and three days later have an “Ah-ha!” moment about how the problems worked that could have slashed my homework time in half. I’d think, “WHY didn’t my teacher just tell me this in the first place?!”

[rogerwood]

We haven't got many tutors in England any way near as good as you. I've followed a lot of your advanced maths and can only say thank you your brilliant. It's extra nice when it comes from a good looker.❤️

[cassied]

Love Krista King's content. Just finished calc II and moving onto calc III. Currently back for some random review before the next semester starts

[Aribrigle]

You did a great job showing all the work, using colors, and explaining everything! More explanation is better than less. Keep up the awesomeness.

[kristakingmath]

i already have a couple on differentials, but i need a lot more, and yes, i will work on getting them posted! :D

[bpjones]

You are amazing! Thank You So Much! Without people like you I would be suffering day in and day out just to understand these concepts. I have never been "naturally" good at math and my teacher doesn't like helping people or even know how to solve the problems herself a lot of the time which ends with a failing class average. I try to teach myself but thanks to people like you I am proud to say I understand Calculus and far above average in my class and now I even enjoy it(especially its applications to physics)! I will definitely use your videos for series and calc. 3 next semester, You are the BEST!

[Miguelperezsierra]

as always youtube is being more helpful than my teachers

[matthewwroblewski]

Clear and concise. It's difficult to find videos on this topic. Thank you so much!

[Abdoolkasim]

I appreciate your effort, Krista and thank you very much for sharing your mathematical knowledge with us!

[pravinmishra]

Crista you teach very good manner I like it and I love you

[matthazard]

That whole "one of the foci is at the pole" bit is what my calc teacher forgot to mention. Thanks a bunch m80 :)

[ThePinoyMamba]

Very solid!

Nice video again!

Sure to be very helpful!

[gonzalezgavino]

Muchas gracias. Cristal-clear explanation.

[kristakingmath]

oh wow, very cool! i LOVED it! such a cool experience, and the crew is an amazing group of people! if you're ever interested in being in the audience, i would totally recommend applying and trying to get in!! :D

[guitarttimman]

I love to see Ladies stepping up to the math plate. 
Home Run! 

[thundercats]

I love your videos! Can you make videos on differentials?

[kristakingmath]

Hi! I explain the process here :) integralcalc . com/how-i-create-my-videos/
As for the ebook, which link is showing the error for you, integralcalc . com/ebook ?

[misseducator]

thanks, i like your videos too much. because they are easy to understand

[Aribrigle]

How do get an e-mail to you to request certain types of problems to be worked out by you? I have some questions about more specific types of parametric equations. Specifically, finding parametric equations for an object in motion and not just for circles.

[nosirrahelocin]

I thought the standard form for conics in polar was (ed)/(1 - e*cos(theta)) where the directrix is x = -d?

[brendanwilson]

I'm confused. The denominator contains addition, 6 + 2cosΘ. How are you allowed to divide by 6 when there is addition? Isn't that a key violation of fraction arithmetic?