Question

How to Work out the nth term in the sequences below?

http://s1274.beta.photobucket.com/user/hmp311/media/7778AD32-3261-48EB-BA9D-119F07AA70C8-1004-00000419CAFB720A_zpsaf8eeb58.jpg.html?sort=3&o=0


Note: I keep asking this and I get a formula:

nth term = dn + (a - d)

Answer 1

@lgbasallote
@nincompoop

Answer 2

Please help:(

Answer 3

what exactly are you asking?

Answer 4

sequence of what?

Answer 5

I dont undersyand how to create a formula.

Answer 6

The worksheet is at the link above.

Answer 7

i see many sequences

Answer 8

It says you have to work out the terms asked for, create a formula.

Answer 9

Actually,all of them. I uave to turn this in today.

Answer 10

well...the formula for arithmetic sequence is what you say \[\huge a_n = a_1 + (n-1)d\]
where:

an is the last term
a1 is the first term
n is the number of terms
d is the common difference

Answer 11

Please know I am in eight grade.

Answer 12

for example

1, 9, 17, 25, 33,...

find the 50th term

an would be a50 because a50 is the last term

a1 will be 1 because it's the first term

n would be 50 because you're looking for the 50th term so you have 50 terms

d would be 8 because it adds 8 each number (1 + 8 = 9; 9 + 8 = 17; etc)

so if you substitute.. \[\huge a_{50} = 1 + (50 - 1)8\]
\[\huge a_{50} = 1 + 49 (8)\]
\[\huge a_{50 } = 1 + 392\]
\[\huge a_{50} = 393\]

so the 50th term is 393 in my example

Answer 13

if you're old enough to learn sequences then you're old enough to learn this

Answer 14

Ok..'reading'

Answer 15

may i try o e?

Answer 16

sure

Answer 17

From my homework.

Answer 18

ill write in othere first amd then type it on here.

Answer 19

sure

Answer 20

a44=8+(5-1)9

Answer 21

number 7

Answer 22

is that correct?

Answer 23

let me check...

Answer 24

ok

Answer 25

number 7 is looking for the 50th term not the 44th

Answer 26

You said a1 was the last term,which in this case is 44

Answer 27

i think you're confused...

8, 17, 26, 35, 44, ....

this doesn't mean 44 is the last term

"..." means the sequence continues

8, 17, 26, 35, 44, 53, 62, 71 and so on

Answer 28

that means the last term is the 50th term because that's what you're looking for

make sense?

Answer 29

ohhhh

Answer 30

well, if we erased the 44, would it be correct?

Answer 31

nope. you used 5 as your n

Answer 32

im sorry.

Answer 33

like i said, the sequence doesn't stop at 44 so there are more than 5 terms

Answer 34

since you're looking for the 50th term, there would be 50 terms

make sense?

Answer 35

yes

Answer 36

good. so rewrite your solution

Answer 37

wait it shouldve been 50 right

Answer 38

a50=8+(50-1)9

Answer 39

right. now solve it

Answer 40

thatll give me the 50th term?

Answer 41

do you solve for a in the a50?

Answer 42

no... a50 means \(a _{50}\) that means 50th term

Answer 43

just solve the right side

Answer 44

-2?

Answer 45

n

Answer 46

no

Answer 47

how'd you get -2?

Answer 48

umm,let me tru again

Answer 49

web2.0calc

Answer 50

ooo the a50 doesnt matter when solving

Answer 51

yes

Answer 52

513?

Answer 53

i lost connection

Answer 54

back,

Answer 55

was i right?

Answer 56

you solved 8 + (50-1)9

right?

Answer 57

yes

Answer 58

did you use a calculator?

Answer 59

yes
i was supposed to use order of operations?

Answer 60

i see what you did

(8 + 50 - 1)* 9

Answer 61

that is wrong

Answer 62

*sigh* ok

Answer 63

you have to do (50 -1)

then multiply it to 9

then add 8

Answer 64

order of ops.

Answer 65

PEMDAS

PARENTHESIS
expoent
MULTIPLICATION
division
ADDITION
subtraction

did you forget this?

Answer 66

no,
thats what order of operations is

Answer 67

parenthesis is (50 - 1)

multiplication is (50-1)*9

addition is 8 + (50-1)*9

Answer 68

that means you do 50 - 1 first

Answer 69

o. so, i use that formula, substitute,and solve right side?

Answer 70

yes

Answer 71

THANK YOU

Answer 72

welcome

Answer 73

hi amistre

Answer 74

i hope im not in trouble @amistre64

Answer 75

finally got to the end of it :) howdy!

Answer 76

howdy,sir

Answer 77

you mean the end of my endless question?

Answer 78

i havent seen the links yet, but lgbas stuff looks good so far

yeah, these things can get rather lengthy, but thats the way we like to see them. lots of interaction and studying instead of rote answers

Answer 79

am i in trouble

Answer 80

lol, not that i can see :) as long as your trying to learn that material you are fine

Answer 81

yes imam.

Answer 82

they all look to be arithmetic progressions, so you can apply the same techniques to all of them

Answer 83

i'd like to know though @amistre64 do you know what dn + (a-d) means?

Answer 84

it looks like the formula for arithmetic progression....but it looks weird

Answer 85

its another way to express the sequence but for n starting at 0 i believe

Answer 86

amistre can i fan u

Answer 87

dn looks really weird

Answer 88

dn + (a-d)

dn - d + a

d(n-1) + a

Answer 89

you can fan whomever you wish

Answer 90

...clever

Answer 91

i think if i get anymore fans the site will collapse into an infinitly large black hole tho so be careful if you do :)

Answer 92

have you gone over how to find the terms used: a, d, n ?

Answer 93

yes

Answer 94

good, cause one you know how to get those, the rest is just simple arithmetic

Answer 95

*cause once you know

Answer 96

d common difference

Answer 97

how do you find the common difference of the sequence?