HP 39g+ - Manual (Page 90)

7-6 Solve aplet
Interpreting results
After Solve has returned a solution, press in the
Numeric view for more information. You will see one of
the following three messages. Press
to clear the
message.
Message Condition
Zero The Solve aplet found a point where
the value of the equation (or the root
of the expression) is zero within the
calculator’s 12-digit accuracy.
Sign Reversal Solve found two points where the
value of the equation has opposite
signs, but it cannot find a point in
between where the value is zero.
This might be because either the two
points are neighbours (they differ by
one in the twelfth digit), or the
equation is not real-valued between
the two points. Solve returns the
point where the value is closer to
zero. If the value of the equation is
a continuous real function, this point
is Solve’s best approximation of an
actual root.
Extremum Solve found a point where the value
of the equation approximates a
local minimum (for positive values)
or maximum (for negative values).
This point may or may not be a root.
Or: Solve stopped searching at
9.99999999999E499, the largest
number the calculator can
represent.