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# Nominal annual interest watch

1. Not sure how to rearrange this equation to find the number of years. So far I've got:
5446.25=5000x(1+(2.5/200))^2n

I think I have to use this formula but not exactly sure, I don't know what In means either:
2. Help, merci
3. (Original post by Kangie)

Not sure how to rearrange this equation to find the number of years. So far I've got:
5446.25=5000x(1+(2.5/200))^2n

I think I have to use this formula but not exactly sure, I don't know what In means either:
Let n = number of "half years". Form an equation in n, and rearrange to solve. You will need to use logarithms! Ln is the natural logarithm, log to the base e.
4. (Original post by lizard54142)
Let n = number of "half years". Form an equation in n, and rearrange to solve. You will need to use logarithms!
I haven't been taught logarithms! We don't have that in the syllabus for maths studies I don't think, if it is then why the hell hasn't my teacher taught me it?!!? D:
5. (Original post by Kangie)
I haven't been taught logarithms! We don't have that in the syllabus for maths studies I don't think, if it is then why the hell hasn't my teacher taught me it?!!? D:
Well you should have been, because it is crucial for this question! You also could do it by "guessing" values of n and seeing which value is closest, you wouldn't need logarithms for that.
6. (Original post by lizard54142)
Well you should have been, because it is crucial for this question! You also could do it by "guessing" values of n and seeing which value is closest, you wouldn't need logarithms for that.
I just found the syllabus and it said: 'Not required:use of logarithms to find n, given the sum ofthe first n terms; sums to infinity.'
I was wondering if this was a trial and error question, wasn't sure though. I guess it is! Thanks
7. (Original post by Kangie)
I just found the syllabus and it said: 'Not required:use of logarithms to find n, given the sum ofthe first n terms; sums to infinity.'
I was wondering if this was a trial and error question, wasn't sure though. I guess it is! Thanks
Okay! So just guess values of n, if the calculation is greater than what you need take smaller n etc... ask your teacher about logarithms, they would give you an exact answer

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