Pre-calc help please!

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thread starter oxwizzaxo Sep 14 2010 + PM | QUOTE | PERMALINK | REPORT

Write the first 5 terms in the arithmetic sequence. Find common difference and write the nth term of the sequence as a function of n. 1. a1 = 15, ak+1 = ak + 4 2. a1 = 72, ak+1 = ak -6 3. a1 = 0.375, ak+1 = ak + 0.25 Thank you!

TronicX 09/14/10 + PM | QUOTE | PERMALINK | REPORT

Sequences aren't Pre-Calculus. They're Algebra/Trig Level at best. Learn your equations and you'll have this down in a flash.

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aznseal 09/14/10 + PM | QUOTE | PERMALINK | REPORT

One thing i've noticed is that most people who ask homework questions are gray blobs. Second is if you want to learn, why not just post one for help instead of your entire homework? We'll help but we won't do your entire homework.

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Orchid 09/14/10 + PM | QUOTE | PERMALINK | REPORT

1. 15, 19, 23, 27, 31... get the pattern?

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oxwizzaxo 09/14/10 + PM | QUOTE | PERMALINK | REPORT

I'm in pre-calc and this is what my teacher is giving me. This isn''t all of my hw anyway, so you're not doing my entire homework. @orchid, how did you find that out, lol

TronicX 09/14/10 + PM | QUOTE | PERMALINK | REPORT

I'll help you out kid, just because I struggled with this when I was in Algebra I. ARITHMETIC EQUATIONS: 1) a(n) = dn + c OR 2) a(n) = a1 + (n-1)d Good luck kid.

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Orchid 09/14/10 + PM | QUOTE | PERMALINK | REPORT

[quote] oxwizzaxo : I'm in pre-calc and this is what my teacher is giving me. This isn''t all of my hw anyway, so you're not doing my entire homework. @orchid, how did you find that out, lol [/quote] uh i just added 4 to each term... i don't remember the equations because it was like last year... i tihnk it was like An=An-1+4. i'm probably wrong.

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oxwizzaxo 09/14/10 + PM | QUOTE | PERMALINK | REPORT

[quote] TronicX : I'll help you out kid, just because I struggled with this when I was in Algebra I. ARITHMETIC EQUATIONS: 1) a(n) = dn + c OR 2) a(n) = a1 + (n-1)d Good luck kid. [/quote] Thank you for the equations, I just have no idea what to plug in or what to do, if you can show me step by step is that's possible I will apply it to the second problem, etc.

Orchid 09/14/10 + PM | QUOTE | PERMALINK | REPORT

[quote] oxwizzaxo : Thank you for the equations, I just have no idea what to plug in or what to do, if you can show me step by step is that's possible I will apply it to the second problem, etc. [/quote] a1 is the first term, d is the common different (for example, the first one was 4), n is the term (as in if you're trying to find the second term, n=2)

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oxwizzaxo 09/14/10 + PM | QUOTE | PERMALINK | REPORT

I know what they all mean. I said I don't know what to plug in or how to find the answers. For example of a1 or d was missing.

Orchid 09/14/10 + PM | QUOTE | PERMALINK | REPORT

[quote] oxwizzaxo : I know what they all mean. I said I don't know what to plug in or how to find the answers. For example of a1 or d was missing. [/quote] wait, but for the problems you posted, there is an a1 and d for all of them..you're just trying to find an

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oxwizzaxo 09/14/10 + PM | QUOTE | PERMALINK | REPORT

i know, i said for example idk how to find each of those things if it's not given. it's just that I have no idea what to do, a subscript k+1 = a subscript k + 4. what od i plug in there

illkoyou 09/14/10 + PM | QUOTE | PERMALINK | REPORT

Oh I see what it's saying. Don't worry about the letters..kinda. Just look at the whole line. You see that: 1. a1 = 15, ak+1 = ak + 4 (for every term +1 starting from the first, you add 4 to the first term)15, 19, 23, 27, 31 2. a1 = 72, ak+1 = ak -6 (for every term +1 starting from the first, you subtract 6) 72, 66, 60, 54, 48 3. a1 = 0.375, ak+1 = ak + 0.25 (for every term +1 starting from the first, you add .25) .375, .625, .875

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oxwizzaxo 09/14/10 + PM | QUOTE | PERMALINK | REPORT

[quote] illkoyou : Oh I see what it's saying. Don't worry about the letters..kinda. Just look at the whole line. You see that: 1. a1 = 15, ak+1 = ak + 4 (for every term +1 starting from the first, you add 4 to the first term)15, 19, 23, 27, 31 2. a1 = 72, ak+1 = ak -6 (for every term +1 starting from the first, you subtract 6) 72, 66, 60, 54, 48 3. a1 = 0.375, ak+1 = ak + 0.25 (for every term +1 starting from the first, you add .25) .375, .625, .875 [/quote] OMg thank you that clears it up a hell of a lot for finding the common difference then the sequence. If you or someone else can help me write the nth term of the sequence as a function of n, i'd greatly appreciate it because then I can apply your help to next problems.

illkoyou + PM | QUOTE | PERMALINK | REPORT

[quote] oxwizzaxo : OMg thank you that clears it up a hell of a lot for finding the common difference then the sequence. If you or someone else can help me write the nth term of the sequence as a function of n, i'd greatly appreciate it because then I can apply your help to next problems. [/quote] I'll try. Give me a second. 1) a(n) = dn + c OR 2) a(n) = a1 + (n-1)d 1. a1 = 15, ak+1 = ak + 4 2. a1 = 72, ak+1 = ak -6 3. a1 = 0.375, ak+1 = ak + 0.25 1) a(n)=15+(n-1)4 15+4n-4 11+4n=a(n) 2) a(n)=72+(n-1)-6 72-6n+6 -6n+78=a(n) 3) a(n)= .375+(n-1).25 .375+.25n-.25 .25n+.125=a(n) I think that's it..I did this 3 years ago haha. Anyway you just plug in whatever term your looking for into the n and you should get the correct term (double check with someone though, I'm rusty in this stuff after doing calc :l)

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