Help with Sequence homework.
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Help with Sequence homework.
For this sequence work out the next term, the rule, the nth term and then work out the 50th term:
15, 11, 7, 3
next term:..........
rule:....................
nth term:............
50th term:.........
Many thanks. Could you explain to me what the nth term means?
15, 11, 7, 3
next term:..........
rule:....................
nth term:............
50th term:.........
Many thanks. Could you explain to me what the nth term means?
Re: Help with Sequence homework.
explanation deleted, realised I was talking rubbish!
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Re: Help with Sequence homework.
What does nth term mean?
Re: Help with Sequence homework.
use this link, my answer was wrong, apologies
http://mathcentral.uregina.ca/QQ/databa ... alex1.html" onclick="window.open(this.href);return false;
http://mathcentral.uregina.ca/QQ/databa ... alex1.html" onclick="window.open(this.href);return false;
Re: Help with Sequence homework.
Can I respectfully disagree? If you say the rule for the nth term is n-4 then the 50th term would be 50-4 = 46.
I agree that you take away 4 to get to the next number in the sequence, so would say that the rule is take away 4 to get to the next term.
But to get the nth term don't you need to work out a formula for the nth term? - and for that you need to show that the first number in the sequence is 15.
I would say that the formula for the nth term is: 19 - 4n
Term 1: 19 - 4(1)
=19 - 4
= 15
Term 2: 19 - 4(2)
= 19 - 8
= 11
Term 3: 19 - 4(3)
= 19 -12
= 7
So, for the 50th term: 19 - 4(50)
= 19 - 200
= -181
Unfortunately I'm not a teacher so I don't know how to show you to get to the formula in the first place. I think Ds would try it as 15-4n or something, realise that didn't work and then get to 19-4n. That's not a great way to teach to apply on other questions though, sorry.
I agree that you take away 4 to get to the next number in the sequence, so would say that the rule is take away 4 to get to the next term.
But to get the nth term don't you need to work out a formula for the nth term? - and for that you need to show that the first number in the sequence is 15.
I would say that the formula for the nth term is: 19 - 4n
Term 1: 19 - 4(1)
=19 - 4
= 15
Term 2: 19 - 4(2)
= 19 - 8
= 11
Term 3: 19 - 4(3)
= 19 -12
= 7
So, for the 50th term: 19 - 4(50)
= 19 - 200
= -181
Unfortunately I'm not a teacher so I don't know how to show you to get to the formula in the first place. I think Ds would try it as 15-4n or something, realise that didn't work and then get to 19-4n. That's not a great way to teach to apply on other questions though, sorry.
The more that you read, the more things you will know.
The more that you learn, the more places you'll go. Dr Seuss
The more that you learn, the more places you'll go. Dr Seuss
Re: Help with Sequence homework.
by all means disagree!
must admit it was a quick answer..!
must admit it was a quick answer..!
Re: Help with Sequence homework.
The link you quote is correct. Your summary of it isn't.yoyo123 wrote:the nth term refers to any number
http://mathcentral.uregina.ca/QQ/databa ... alex1.html" onclick="window.open(this.href);return false;
Re: Help with Sequence homework.
n=1 for the first term, 2 for the second term, etc. Hence, as JRM says, the rule is 19-4n (if you were writing it formally, it would be something like x subscript n = 19 - 4n).Pumpkin Pie wrote:What does nth term mean?
An arithmetic sequence (those where the difference between successive terms is constant) will be of the form x sub n = a + bn. You can get b simply by looking at the difference between terms, and is here -4. Then you solve for a: you've got 15 = b - 4x1, so b is 19.
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Re: Help with Sequence homework.
May I ask, what year homework is this? Year 5? Or 6?
Seize the day ... before it seizes you.
Re: Help with Sequence homework.
The common difference between terms in -4 so the rule must be based on the -4 times table ie one part must be -4xn
We then need to make the rule fit starting at 15 ... so the nth term is 19-4n
OK?
We then need to make the rule fit starting at 15 ... so the nth term is 19-4n
OK?