When Can't Find A Solution; Obtaining More Information About; Results - HP -225 Owner's Manual

When Can't Find a Solution
There are two general situations where may fail to find a
solution:
m may be unable to find a value that sets the left side of the
equation equal to the right side. The HP-22S displays
NO ROOT FHND. For example, the equation:
ABS(X) +¥Y=8
has no solution when Y > 0, since X| can never be negative.
u may encounter a math error if an estimate generates an
unallowed operation. For example, attempting to solve:
Xi¥-12=2
for X with Y=0 displays DIVIDE BY 8.
See appendix B for additional information.
Obtaining More Information About Results
Appendix B covers this topic in more detail.
More Information About Answers. When returns an an-
swer, pressing [LAST] displays the value left — right, where left and
right are the values of the left and right sides of the equation when
the answer is substituted into the equation. The value in LAST should
be zero or a very small number.
More Information About NO ROOT FND. When returns
NO ROOT FHND, press to display the final estimate for the un-
known. Then, press @[LAST] to display the value of left —right, where
left and right are the values of the left and right sides of the equation
when the estimate is substituted into the equation.
More Information About Math Errors. When returns a
math error, press unknown variable to view the final estimate.
Sometimes this value can help you diagnose why failed to
find a solution.
90 6: Evaluating and Solving Equations