Infinite series as limit of partial sums | Series | AP Calculus BC | Khan Academy

Infinite series are defined as the limit of the infinite sequence of partial sums. Since we already know how to work with limits of sequences, this definition is really useful.

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[MissyEmz]

Just a quick tip for anyone that's confused with with he divided by n^2 and not n^3: usually you want to divide by either the highest power overall or the highest power in the denominator, either way you get the same result.
For example, if he divided by n^3 he would have gotten 2/0 which would still approach infinity.

[Saintsheeps]

I’m sill in middle school I just like his voice

[hassjazzi]

Very good explanation: VERY BASIC THOUGH BUT IT GOT ME UNDERSTANDING: THX MUCH :)

[RajatSharma-ccjh]

sir plz make the videos of fermat's little therome 

[circuitguru]

Great Video, but I think Sal should SLOW down

[shidaothman]

im sorry but this chpter is quite hard for me. why u used lim Sn to know if it coverges or diverges? cant we just use lim an? why

[clairex]

stop repeating every phrase a million times while youre writing PLEASE it pisses me off and no i will not just stop watching

[Bigmanchris]

@3.23 i thought you divide by (n^3). the highest exponent.

[dscruiter]

why are u dividing by n^2 and not n^3?

[drakefire]

This is not correct. The lim of a partial sum is not always 100% equal to the series sum. Only in certain cases like geometric when the series converges.

[TheodoreCackowski]

Reuse of 'n' in both the first equation as the index and subsequent equations as the upper bound in the partial sum ... thumb down