Solving for single variable proving to be extremely difficult.

Question

I have been at this equation for about two days now, and I can not for the life of me find a way to solve to i. If anyone can please show me a step by step into solving this, it would help me out so much. This equation was created by myself to show how compounding interest works if you add the original amount after each year. Please help me solve for i

$F = P(1+i)[\frac {(1+i)^n-1}{i}]$

solve for $i$

There is no closed form formula for $i$ when $n\ge 4$. One has to use a numerical method. — André Nicolas, Apr 10 '15 at 16:52
This computation is typically done using a financial calculator. All other variables are known, so you can usually enter their values and ask the calculator to find $i$. — MPW, Apr 10 '15 at 16:54
I understand, but I would like to formulate my own formula for finding i, i understand a calculator could do it. — Uys of Spades, Apr 10 '15 at 16:54
I believe the calculator does the problem numerically. There is not an explicit formula for $i$. — MPW, Apr 10 '15 at 16:55
@UysofSpades It is a theorem that there is no closed form formula as Andre commented when $n≧4$. — Rubertos, Apr 10 '15 at 16:56
@Rubertos so the only hope to find i is to use a scientific calculator? — Uys of Spades, Apr 10 '15 at 16:57
Note that is is definitely NOT true that you can't solve any polynomial equation of degree at least $5$. What's true is that there is not a general formula. Some specific cases can indeed be solved. I don't know if this is one of them. — MPW, Apr 10 '15 at 17:00

score 0 · Accepted Answer · edited Apr 13 '17 at 12:21

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Better read through this How to solve an nth degree polynomial equation We can't solve algebraically for a polynomial with degree greater than 4.And you dont need to either.If you know the values of the other variables just put them in and use a computer program http://www.wolframalpha.com/ to solve for it.

edited Apr 13 '17 at 12:21

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answered Apr 10 '15 at 16:58

Solving for single variable proving to be extremely difficult.

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