HP 39g+ - Manual (Page 89)

Solve aplet 7-7
If Solve could not find a solution, you will see one of the
following two messages.
H I N T It is important to check the information relating to the solve
process. For example, the solution that the Solve aplet finds is
not a solution, but the closest that the function gets to zero.
Only by checking the information will you know that this is
the case.
The Root-
Finder at work
You can watch the process of the root-finder calculating and
searching for a root. Immediately after pressing
TPGW@— to start
the root-finder, press any key except
>21@. You will see two
intermediate guesses and, to the left, the sign of the expression
evaluated at each guess. For example:
+ 2 2.219330555745
– 1 21.31111111149
You can watch as the root-finder either finds a sign reversal or
converges on a local extrema or does not converge at all. If
there is no convergence in process, you might want to cancel
the operation (press
>21@) and start over with a different initial
guess.
Message Condition
Bad Guess(es) The initial guess lies outside the
domain of the equation. Therefore,
the solution was not a real number or
it caused an error.
Constant? The value of the equation is the same
at every point sampled.