# Complicated Algebra, though I reckon theres a simple answer!

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• Oct 11th 2009, 04:48 AM
ryanhorne
Complicated Algebra, though I reckon theres a simple answer!
I have been out of eduacation for while so am a bit rusty on my maths, but basically I started with a binomial expansion and have windled it down to the following alebraic equation which i cant seem to simplify anymore!

(n/9)*0.9^n + 0.9^n = 0.5

And obviously im trying to find n, which I know is around 16.5, but only through guessing!
• Oct 11th 2009, 07:30 PM
mr fantastic
Quote:

Originally Posted by ryanhorne
I have been out of eduacation for while so am a bit rusty on my maths, but basically I started with a binomial expansion and have windled it down to the following alebraic equation which i cant seem to simplify anymore!

(n/9)*0.9^n + 0.9^n = 0.5

And obviously im trying to find n, which I know is around 16.5, but only through guessing!
[IMG]file:///C:/DOCUME%7E1/RYAN2%7E1/LOCALS%7E1/Temp/moz-screenshot.png[/IMG][IMG]file:///C:/DOCUME%7E1/RYAN2%7E1/LOCALS%7E1/Temp/moz-screenshot-1.png[/IMG]

An exact answer cannot be obtained using algebraic methods (unless you introduce new functions). Why do you rquire an exact value? And if you don't, then just use technology to solve to required accuracy.
• Oct 12th 2009, 07:43 AM
ryanhorne
I agree
Yes, I do not think a value of n can be obtained from this, as I have spent hours slaving over this! So will have to use Excel.

Cheers for your help
• Oct 12th 2009, 08:52 AM
eeyore
I don't know how to solve this problem, but I do have mathematica and I think that's a better tool than excel. (Itwasntme)

The answers are $-6.802379497590862, 16.441793453448483$