Geometric sequences | Sequences, series and induction | Precalculus | Khan Academy

[@KylasVlogs]

I'm so freaking confused this has to be the worst unit we have learned so far

[@Indian_.mappings.]

innit

[@GeedaarKhan]

@@Indian_.mappings. unnit

[@Bloodre1]

Yes, he speaks english.

[@saminm1]

I hope you done some videos about the sum of both types of sequences with their proof

[@teabiscuit2618]

I would probably fail my igcse exams if your vids didn't exist.

[@andreburruss11]

don't overcomplicate it dude

[@catherinekobleyberke2849]

Love how easy you make this to understand.

[@shiratori88]

Thanks

[@greerhanshaw]

Does a geometric sequence start at 0 or 1? I see different representations across websites. Is it my choice to decide whether to start at 0 or 1?

[@ArjunTanwar900]

if u take 0 as your first term , then you'll have to multiply 0 by the common ratio to get the 2nd term, which will give u 0 again

[@madpennyando9782]

could anyone help me with compound interest that also has deposits

[@ohgodyourefat4787]

🔇GET 🔇BACK 🔇TO 🔇LEARNING 🔇STOP 🔇LOOKING 🔇THROUGH 🔇THE 🔇COMMENTS 🔇

[@78anurag]

No u

[@tar0286]

I thought that sequences were only allowed to change by a fixed amnt each time, in a linear fashion. Why is he allowed to multiply 'a' by 'r' (a x r ) each time?

[@thaaohanshew4531]

When they change by a fixed amount, that's an arithmetic sequence. Geometric sequences change by a fixed factor. So, your understanding is correct, but for a different type of sequence than the one discussed in the video.

[@tar0286]

Thanks for the clarification Thaao, nice name too

[@thaaohanshew4531]

Haha, thanks

[@blitzwaffe]

This video is great for review in my class :)

[@78anurag]

Do you have kids now

[@c9gaming368]

yes, but how do I find the ratio with 2 separate numbers: a(1), 20, a(3), 11.25, a(4). That is what I have been trying to get answered for the past 3-4 hours. I am almost locked out of the quiz because of winging it off of so many videos.

[@robb_f]

Hello C9 Gaming, I understand I'm 5 months late, so if I don't serve assistance to you, hopefully it helps someone else. *I wrote a(n) as "a sub n" since I can't do subscripts. Likewise for all other cases.* The general formula for geometric sequences is a(n) = a(1) * r^(n - 1). Let me use your example as the tool to help. We're given a(1) = 20, and a(3) = 11.25 We're first given a(1), so now we just have to find the ratio. The easiest way to find the ratio is by using the formula above, and plugging in the 2 values you're given. Let me demonstrate: a(n) = a(1) * r^(n - 1) a(3) = a(1) * r^(3 - 1)

[@mattsunderesmakki8161]

@@robb_f did you use linear equation?

[@robb_f]

@Shyra Claudio No such thing, it's a geometric sequence, not the equation of a line.

[@mattsunderesmakki8161]

@@robb_f sorry it's just so hard for me. Now I'm getting equations mixed up

[@robb_f]

@Shyra Claudio It's okay. Theoretically, you could use this as a linear equation. Usually, we use tables or just a list (showing terms). With a graph, we would just have to use points to find the term and the value.

[@alanrasch9511]

Dat OCD in the beginning ^^

[@IncelCherub]

my pre calc professor is an old guy with a thick Russian accent that doesn't speak very loud and has a mask on...

[@gtxhunter1720]

why does my homework say Geometric sequence A(n)=a(1)(r)^x and it works for my awnsers but then another sheet says a1(r)^x-1

[@Brandon-xm4mp]

well, some goemetric sequences, the starting term or base term is known as the 0th term of the sequence which in that case the exponent for r is just x or sometimes n. However, if the base of the sequence is known as the 1st term, that's when you will need the exponent of r to be x-1. Both equations represent geometric sequences tho, they are just represented differently. The base term of a geometric sequence is the starting number that hasn't been multiplied with the constant yet.

[@Brandon-xm4mp]

im not sure if that helps

[@gtxhunter1720]

Hey man i apreciate your response but its been a while so i might have to refresh this lmao. wow. I dont even remember that class

[@Brandon-xm4mp]

@@gtxhunter1720 lol its ok

[@matabeleman]

are you speaking english..I cant seem to understand what you are saying? are you just making this up as you go along?

[@ArjunTanwar900]

matabeleman its clearly korean

[@channelkylexyree4246]

No Salt lmao

[@Indian_.mappings.]

absolue horrible teaching