Radius of convergence (KristaKingMath)

Learn how to find the radius of convergence of a series using the ratio test.

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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?!”

[davidgoni]

I just wanted to say thank you so much for making this video. I'm taking BC Calc at school and I learned more in this ten minute video than I did in the day we spent on this because you take your time to explain every single step including subtracting the exponents and everything. Again, thank you. Five star teaching. (:

[EllenMoment]

you've been sent from the gods to save my life!! I appreciate this so much, thank you!

[portalghst]

You're the first one to explain why it is ok to have abs(x - a) and why it's not ok if you have a constant in front like: 4abs(x-a) when looking for the radius of convergence. Thank you. You teach math as it should be taught!

[mohdhafizulkhairimohdrazal]

Please continue your teaching . I am taking calculus 2 this semester .Thank you so much .I like your video because your pronounce is very clear

Thanks for the help. Every word you spoke is stuck in my head. Beautiful voice

[kosmicseduxion]

Thank you very much. You have really helped me in Calc 2. Series and sequences can be a pain but with your help it is so much better.

[cyrilferrero]

Of all the channels, this is the best. thak you very much for making videos about such topics i really appreciate it. love you.

[satanicmonkey]

Explained way better than my teacher and the book itself. I just subscribed.

[shrutisarkar]

Thank you so much for making the way more easier to us.

[mbenitezusmc]

OMG I just fell in love with my new math teacher :D

[Hasko-jt]

Thank you so much for making calculus easier for us.

[justingallagher]

Dear IntegralCalc gal,

I am taking Calc III this summer.  Please don't stop making videos.  I need you.  

Sincerely,
J

[horselover]

Your videos are very helpful, thank-you for dedicating some time to help others with math. Having recently started the taylor series (and thus not knowing much about it), I would like to know why, exactly do people need to find its radius of convergence? What practical use does it have?

[ILaCkPeArL]

~6:34 you calculate that n-(n+1) = n-n-1 = -1. But then you continue with 4*n. Isn't it 4^-1 = 1/4*n = n/4?

[stevekhan]

I have a curious question what if we get -1<x^2<1 after taking the ratio 
test ? is the radius of convergence simply (1) and interval of convergence (-1, 1) ?

[aaronasmr]

Could you go over testing the end points ...that's the hard part

[saveUyghurs]

At 1:33 she says all of that stuff was equal to a sub n. I thought power series were in the form a sub n times x^n, so wouldn't that make only the stuff before (x+3)^n equal to a sub n? Hope that made sense and that someone could clarify for me.

[matiasavila]

Hi, which program do you use to write like a blackboard

[frankstn]

you explain too good .. !! Thank you so much.. :-)

[bilalrana]

I'm actually going to calculus next year and I do not want any trouble before the year starts, what should I do?
 -Oh and you are CUTE (I could not help myself)