Algebra 2 Sequence help?
Okay I really don't understand these when it comes down to sequences.
There are like so many formulas and now I don't know which ones to use.
So you really don't need to give me the answer but like I don't know how to start/use which formulas to start.
[url=http://28.media.tumblr.com/tumblr_m39845aQPn1qf4pfwo1_500.jpg]Finest of the uploads.[/url]
The link is weird so just copy and paste it again starting from 28.
April 29, 2012
5 Comments • Newest first
[quote=Momo123]This is algebra 2.... i'm learning this in pre calc and this is my last section lol[/quote]
Well Algebra 2/Trigonometry is my 3rd year math course for high school and I took Algebra 1 in the 8th grade so yeah. I have no clue why they call it Algebra 2 when it's like Algebra 3 if you follow the way the school goes LOL
Aw I have to take Pre-Cal next year for my placement into AP Calc </3 Long process.
This is algebra 2.... i'm learning this in pre calc and this is my last section lol
[quote=TheTuvvo]1. If I'm correct, you shouldn't have to use any formulas for this one. Just plug in 1, 2, 3, 4, and 5 for n in the given formula.
First 5 terms: 2, -2, -6, -10, -14
It is arithmetic because you can see that it is decreasing by 4 each term (the common difference, d).
2. Once again, just plug in the first 5 terms.
a)
First 5 terms: 3/2, 1/2, -1/2, -3/2, -5/2
Then graph them as (n,an) Ex. (1,3/2) (2,1/2)
b)
You should get a straight line, with the slope -1, I think.
c)
To find the common difference, d, use the formula an=a1+(n-1)d
1/2=3/2+(2-1)d
-1=(1)d
-1=d
3. The sequence is an arithmetic progression. First you need to find the 35th term by using the formula an=a1+(n-1)d:
a35=7+(35-1)2
a35=75
Then use the sum formula Sn=n/2(a1+an)
S35=(35/2)(7+75)
S35=1432
4. The sequence is also an arithmetic progression.
Use the formula an=a1+(n-1)d, solving for an.
an=30+(n-1)-4
an=30-4n+4
an=34-4n
Plug it into the formula Sn=n/2(a1+an) and solve for n.
-210=(n/2)(30+34-4n)
-210=(n/2)(64-4n)
-210=32n-2n^2
-105=16n-n^2
n^2-16n-105=0
(n-21)(n+5)=0
n= 21, -5
n MUST be a positive number so [b]n=21[/b][/quote]
Oh my! Thanks so much!
(I actually forgot that n was actually the term number so I was confused from there, oops.)
And I kind of did each question myself and if I was stuck, I checked it and saw what I did wrong.
Thanks so much! <3
[quote=Watermelon]Does all American math books have a space for you to answer below the question? Like don't you have to do it on a notebook or something?[/quote]
Haha, I guess it's easier for the teacher to check it and for the students to do.
Does all American math books have a space for you to answer below the question? Like don't you have to do it on a notebook or something?