Question

Find nth term arithmetic sequence whose 1st term is

10 and whose 21st term is 0.

Answer 1

solomon, any tips or hints?

Answer 2

you still there by the way?

Answer 3

ahh

Answer 4

you got disconnected again?

Answer 5

Finally.

Answer 6

What do you know?

Answer 7

use the formula
\(\large a_n = a_1 + (n-1)d\)

Answer 8

Oh my bad....

Answer 9

a1 = 10 is given
for 21st term
put n= 21
and a21= 0

Answer 10

so... I'm sorry, I'm kinda just learning this stuff myself because my teacher

has alot of trouble speaking English :(

Answer 11

solomonzelman, could you run that by me again?

Answer 12

yes, I can show you an example or a couple.

Answer 13

I'm kinda of a step-by-step kind of guy

Answer 14

you noted down the formula ?

Answer 15

yes

Answer 16

so

Answer 17

wat does a n, a1, n, and d stand for?

Answer 18

ok,
a_n is the n'th term
a1 = 1st term
d= common difference

Answer 19

so, 21st term = 0
means
we put n=21

Answer 20

and an=0

Answer 21

ok, so wait

Answer 22

let me work this out

Answer 23

so a1=10, right?

Answer 24

yes

Answer 25

yes, a1 = 1st term = 10 is given

Answer 26

ok

Answer 27

so wait

Answer 28

I'm trying to think here

Answer 29

if a1=10, wat would a n and n stand for?

Answer 30

a_n is the n'th term
like
a1 = 1st term
a2 = 2nd term
a3 = 3rd term
a4 = 4th term
and so on

Answer 31

\[a_n\]is the nth term, or in your case 21st.

Answer 32

ahh

Answer 33

so 0=10+(n-1)d?

Answer 34

am I getting there yet?

Answer 35

I think we can do an easier example to get it conceptually, real quick,

Answer 36

ok

Answer 37

0 = 10 + (21-1)d
remember that n = 21, right ?
because 21st term was given = 0

Answer 38

Lets say you have an arithmetic sequence,\[1,4,7,11.....\]and you have to find the 10th term

Answer 39

So far so good?

Answer 40

35

Answer 41

You have a formula, \[a_n=a_1+d(n-1)\]

Answer 42

how, what did you do to get 35?

Answer 43

I counted in my head

Answer 44

Using formula or adding?

Answer 45

adding

Answer 46

Don't do this, becuase you won't be able to count 10000th term.

Answer 47

though it generally only works for small units

Answer 48

I know

Answer 49

look

Answer 50

a n=1+(10-1)d?

Answer 51

is that any better?

Answer 52

i don't about d though :(

Answer 53

I don't know about d

Answer 54

Don't do this, becuase you won't be able to count 10000th term.

Answer 55

hmm?

Answer 56

what do you mean, I am using the formula now

Answer 57

I snapped again.

Answer 58

I'm just trying to figure out know about the common difference

Answer 59

and what it exactly stands for