HP 32SII - Manual (Page 329)

More about Solving C–15
File name 32sii-Manual-E-0424
Printed Date : 2003/4/24 Size : 17.7 x 25.2 cm
function never changes sign SOLVE returns the message  !  .
However, the final estimate of x (press @ to see it) is the best possible
12–digit approximation of the root when the routine quits.
Underflow
Underflow occurs when the magnitude of a number is smaller than the
calculator can represent, so it substitutes zero. This can affect SOLVE results.
For example, consider the equation
2
1
x
whose root is infinite in value. Because of underflow, SOLVE returns a very
large value as a root. (The calculator cannot represent infinity, anyway.)