Register to reply

Sequence formula [itex]a_{n}[/itex]=((last term) - (n-1)(common diff))

by Lebombo
Tags: anlast, diff, formula, n1common, sequence, term
Share this thread:
Apr17-13, 08:31 PM
P: 136
Calc 2 will require some basic knowledge of sequences and series. Since this topic has never been covered in any of my past math classes, I am currently learning about sequences and series from scratch. On youtube, I found a video that contains an explanation of the General Term of the Arithmetic Sequence formula. It also contains another form which does not exist in my Algebra Textbook:

[itex]a_{n}[/itex] = ((last term) - (n-1)(common diff))

However, I think the person providing the youtube explanation makes a mistake in notation, which is causing me some confusion. If he has written this portion of his presentation correctly, then I will have to go back and review my confusion. So if anyone has a moment, could you fact check the portion of the derivation of this formula at exactly 9:16 - 9:23

To me it seems [tex]a_{n}- a_{n-1} [/tex] should equal d, not -d , so did he intend to write [tex]a_{n} - a_{n+1} = -d[/tex]
Phys.Org News Partner Mathematics news on
Math journal puts Rauzy fractcal image on the cover
Heat distributions help researchers to understand curved space
Professor quantifies how 'one thing leads to another'
Apr18-13, 10:37 AM
ArcanaNoir's Avatar
P: 754
Yes this is a mistake. I think he meant to have [itex] a_n-a_{n+1}=-d [/itex]

I watched the video but I didn't listen to it because I'm in class.

Register to reply

Related Discussions
What does [itex]\zeta(s)/s[/itex] converge to as [itex]\Im(s)\rightarrow\infty[/itex] Calculus 10
Show [itex]\phi[/itex][itex]\circ[/itex]f is Riemann integrable Calculus & Beyond Homework 5
Prove [itex]C[a,b][/itex] a closed linear subspace of [itex]L^{\infty}[a,b][/itex] Calculus & Beyond Homework 1
Proofs, [itex]\exists[/itex] x [itex]\in[/itex] (1, [itex]\infty[/itex]) such that... Calculus & Beyond Homework 6
Show seq. [itex] x_n [/itex] with [itex] |x_{n+1} - x_n| < \epsilon [/itex] is Cauchy Calculus & Beyond Homework 2