HP HP-15C

186 Section 13: Finding the Roots of an Equation
Fahr's ridget falls to the ground
9.2843 seconds after he hurls ita
remarkable toss.
When No Root Is Found
You have seen how the _ key estimates and displays a root of an
equation of the form f(x) = 0. However, it is possible that an equation has no
real roots (that is, there is no real value of x for which the equality is true).
Of course, you would not expect the calculator to find a root in this case.
Instead, it displays Error 8.
Example: Consider the equation
|x| =  1.
which has no solution since the absolute
value function is never negative. Express
this equation in the required form
|x| + 1 = 0
and attempt to use _ to find a
solution.
G
r
G
Keystrokes
Display
| ¥
000–
Program mode.
´b 1
001–42,21, 1
| a
002– 43 16
1
003– 1
+
004– 40
| n
005– 43 32