nth term homework yr 7

[Christywhisty]

Ds has nth term as homework, most of it is okay and he understands it, fairly simple answers like 5n-2 etc

But the following just seem way too complicated

3,7, 11, 14, 18

the differences don't seem to make sense ( 4, 4, 3, 4,)

also

1, 8, 15, 22, 27

differences

(7, 7, 7, 5)

Any ideas, have tried squaring them etc
I am almost starting to think there are printing errors!

Can you give a couple of examples of ones which do make sense to you - maybe that'll help us see some kind of pattern?

are the answers in the back? might tell you if they are printing errors

What are they asking him to do? Continue the sequence? State the rule governing the sequence?

the ones that ds has managed are

3,8,13,18,23
which is 5n-2

9,14,19,24,29
which is 5n+4

8,12,20,26,32
which is 6n+2

he has to state the rule ie 6n+2 then find the next 2 in the sequence and also find the 10th and 50th in the sequence

Sorry. I don't understand it. I am too dense to work out what variable n is standing in for.

Sorry - don't understand the ones you've got let alone the ones you haven't!!

So, for the 5n-2 one, number 1 in the sequence = 5x1 - 2 and number 2 in the sequence is 5x2 - 2 etc?

Ah!! Thamks, AMuminScotland.

Ah - light switches on

Sorry Threadworm - I'm not copying everything you say on purpose!

so n (1, 2, 3...)
is for all of them ?

Still doesn't solve the others though...

The ones your DS has managed all go up a regular amount each time, which they would have to for any 5n - 2 or similar type of equation (except you've got a typo in your last example - 12 instead of 14). So the others either have typos, and are meant to be a regular progression or else they'd have to be squares or something more complicated - buthen they'd go up faster as they went on, which they don't....

I'd be tempetd to rewrite them with a regular difference, and assume the're typos...

Couldn't the pattern for the first one be 4,4,3,4,4,3 etc. Or am I being really dense.

In my defence I'm only used to year 1 maths

variable n = 1,2,3 etc

so if nth term is 5n+4
then
1 is 5x1=5 +4 =9
2 is 5x2=10 +4 =14
3 is 5x3= 15 +4 =19

you have the sequence
9,14,19 24 29 etc
the 10th term will be
10x5 =50 +4 =54

Like some of mine...

Oops sorry cross posted.
You could do the sequence, but he still needs to know the algebraic formula for it.
Yes there was a typo it should have been 14, not 12

are you still stuck my dd will have a go now

Yes still stuck
glad it's not only me and ds,

can you confirm the numbers is it

3 7 11 12 18

no it's 3,7,11,14,18
the typo was in one ds has done already

the other one that needs doing is

1, 8, 15, 22, 27

There must be a mistake in these - the second one is 7n-6 except for the last number. Still trying the first one!!

it must be a printing error as ds who's doing A-Level maths says its complicated- not even A Level standard. You could try working it out using sequence
3, 7, 11, 15, 19
and then the rule would be 3n+2

and for the other one it could be
1, 8, 15, 22, 29
and the rule would be 7n-6

Snap, soremummy!!!