Section 13: Finding the Roots of an Equation 183
Keystrokes
Display
´_
0
5.0000
The desired root.
After the routine finds and displays the root, you can ensure that the
displayed number is indeed a root of
f(x)
= 0 by checking the stack. You have
seen that the display (X-register) contains the desired root. The Y-register
contains a previous estimate of the root, which should be very close to the
displayed root. The Z-register contains the value of your function
evaluated at the displayed root.
Keystrokes
Display
)
5.0000
A previous estimate of the
root.
)
0.0000
Value of the function at the
root showing that
f(x)
= 0.
Quadratic equations, such as the one you are solving, can have two roots. If
you specify two new initial estimates, you can check for a second root. Try
estimates of 0 and -10 to look for a negative root.
Keystrokes
Display
0
v
0.0000
Initial estimates.
10
“
–10
´
_
0
–2.0000
The second root.
)
–2.0000
A previous estimate of the
root.
)
0.0000
Value of
f(x)
at second root.
Summary of Contents for HP-15C
Page 1: ...HP 15C Owner s Handbook HP Part Number 00015 90001 Edition 2 4 Sep 2011 ...
Page 17: ...Part l HP 15C Fundamentals ...
Page 64: ......
Page 65: ...Part ll HP 15C Programming ...
Page 118: ...118 ...