Thread: algebra equation
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Old 05-12-2008, 12:25 AM
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Quote:
Originally Posted by ecstyle View Post
I am trying to solve for the variable i but I can't seem to do it. I've tried various ways but get totally lost towards the end.

Here is the equation:
(Note: x is not a variable, it indicates multiplication here)

10.5754 x i = 1 -[1/(1+i)^12]


I know that the answer is .02 or 2% but I can't seem to figure this out and its driving me crazy.

Any suggestions or help is greatly appreciated!
Maxima gives the real roots as, approximately, i=-1.779662862165678,\ 0,\text{ and }0.019999092385499.

The exact solution would probably require factorization of

12553\,{i}^{12}+149449\,{i}^{11}+814254\,{i}^{10}+2683318\,{i}^{9}+5952595\,{i}^{8}+9354411\,{i}^{7}+
10658868\,{i}^{6}+8845188\,{i}^{5}+5273631\,{i}^{4}+2174095\,{i}^{3}+567358\,{i}^{2}+72294\,i-1691,

which is by no means easy or feasible. Numerical or graphical approximation is the way to go here.
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