a financial problem again



On 03/27/2012 04:13 PM, Victor Hermans wrote:
> Maxima cannot solve this relatively simple problem. Why?
>
> A principal of USD 7650 is invested at a rate of 3.7% compounded annually.
> After how many years will the investment exceed USD 12250?
>
Hi,
some developers with more experience than me will tell you why Maxima 
has been built that way.

In the meantime, you can give "solve" a little help to get the answer 
you want:

(%i2) logexpand: all$
(%i3) solve ( log(7650*1.037^x=12250), x);
(%o3) [x = (193246*log(12250)-193246*log(7650))/7021]
(%i4) float(%);

(%o4) [x = 12.9588573703922]

Cheers,
Jaime