Limit comparison test | Series | AP Calculus BC | Khan Academy

In some cases where the direct comparison test is inconclusive, we can use the limit comparison test. Learn more about it here.

AP Calculus BC on Khan Academy: Learn AP Calculus BC - everything from AP Calculus AB plus a few extra goodies, such as Taylor series, to prepare you for the AP Test

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[MauricioMartinez]

Jesus man you're fucking awesome. Theres a lot of other good teachers on youtube, like professor leonard, and partcikjmt and such, but the one thing about your teaching is that you get the point across quickly. I dont have to spend 2.5 hours watching a whole lecture, or 6-7 different videos. You give us the theorems, maybe an example here and there, in like a 6 minute video. Thanks khan academy. Ya'll know whats up

[vee-ec]

Thanks a bunch!! Really well done, i understood direct comparison test but LCT flew over my head until now.

[tejasgajra]

If lim (an/bn) = t (t>1)
Then an > bn ... If bn converges then it is not necessary for "an" to. Converge...
Pls can you prove the theorem?

[HighStar]

are there more specific requirements for bn?
like if an is 1/2^n can i just set bn at 100^n?

[walkieer]

For the second example can you use the traditional comparison test and say 1/1^n >= 1/(2^n - 1). Or is there something wrong there?

[rashmikababajee]

helloo,

your tutorials are amaazzinnggg :D

the only thing that I fail to understand is when do we know when to put n=1 or n=0 below the sigma notation...

Can somebody please explain it to me :)

Thanks in advance:)

[joshuachamblee]

Why did he divide the numerator and the denominator by 2^n at 5:45

[yashraj]

Plz give homework questions at the end of your videos plzzz

[muscalddict]

So one use the limit comparison test when the direct comparison test gives you and inconclusive answers????

[kyro]

But (1/2^n) doesn't Converge, it Diverges and is a Harmonic Series right?

[VickiBee]

What is this called? Calculus?
The doctor treating me now says I have a tumor on the right side of my brain but that makes no sense because I've never felt pain on the right side, only on the left. He's got me all confused. I've always been left-handed and used my right brain side more than the left and now he's telling me they found a hemangioma on the right side. 
When you do math you use the left side of your brain, which always hurts when I use it too much. I've never felt a headache on the right side of my head, only the left. That's what makes me think is the reason I'm so lousy at math.

[moose]

But what if the limit is zero when you do lim comparison. It's not positive??

[MrBoriskaful]

I dont know when to use which method AHHH my exam is on saturday

[uduak-abasiamana]

what does he mean by positive and finite?

[shayorshayorshayor]

What if the limit comparison test equals 0?

[bageoop]

Khan Academy has 1 million subs and this video has 0 comments? huh