# [Maxima] Solving an equation

Richard Fateman fateman at cs.berkeley.edu
Fri Jun 22 14:46:02 CDT 2007

```Solve doesn't  do anything useful  with  exponents like 0.68.

Converting 0.68 to an exact rational,  17/25,  it is possible to
transform your
problem into a polynomial of degree 17  in a^(1/25).  Where b=a^(1/25),
the equation
looks like

128575 * (qs^(1/25))^17 * (r^(1/25))^17
* (((1/ssvi))^(1/100))^77 * b^25
+ ( - 419 * mlss * qs * r - 419 * mlss * qs) * b^17

or  k1*b^25 +k2*b^17.

for some messy constants k1, k2.   There are 9 solutions, one of them
being b=0, with multiplicity 9.

RJF

Dudley, Jeremy wrote:

>I define
>
>(%i1) X: Qs * MLSS * (1 + r) / A
>
>(%i2) X = 8.85 * (100 / SSVI)^0.77 * (Qs * r / A)^0.68
>
>(%i3) solve(%i2, A)
>
>Expecting to get A = f(Qs, MLSS, SSVI, r)
>
>Instead I get A on both RHS & LHS, and cannot find a suitable 'simplify'
>command to get the equation fully explicit in A.
>
>How do I persuade Maxima to give me a fully explicit solution?
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```