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11,406.14=(438.3/r)(1+r)^10 how do you solve for r?

  • calculus -

    These are very "nasty" equations, since there is no simple-level method of solving these.
    I reduced it to
    (1+r)^10 = 26.02359r

    If you know Calculus, you can use Newton's Method,
    otherwise, try something like this

    It looks like your equation could have come from the amount of an annuity formula, so the r is probably an interest rate
    make a chart with 3 columns
    r | Left Side|Rigth Side
    .05 1.62889 1.3 ---- off quite a bit
    .06 1.79084 1.5614 --- let's go higher
    .09 2.36736 2.345 --- hey, not bad
    .095 2.4782 2.47224 -- closer !!
    .096 2.50095 2.49826
    .097 2.523866 2.524288 notice the Right side is now > the left side
    so our r must be between .096 and .097

    try .0965
    Do you get the idea?

    With a good calculator and some calculator skills this is not so bad
    BTW, I put 26.02359 into memory of calculator

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