HP 40gs HP 39gs_40gs_Mastering The Graphing Calculator_English_E_F2224-90010.p - Page 84

Finding and accessing polynomial roots, view as shown. This method works equally well

Page 84 highlights

Finding and accessing polynomial roots The POLYROOT function can be used to find roots very quickly, but the results are often difficult to see in the HOME view due to the number of decimal places spilling off the edge of the screen, particularly if they include complex roots. This can be dealt with easily by storing the results to a matrix. For example, suppose we want to find the roots of f (x) = x3 − 3x2 + 3 . We will use the POLYROOT function and store the results into M1. The advantage of this is that you can now view the roots by changing to the Matrix Catalog (SHIFT 4) and pressing . See page 209 for more detailed information on matrices. In addition to this, you can access the roots in the HOME view as shown. This method works equally well for complex roots. See page 309 for details on finding roots of real and complex polynomials using the CAS on the hp 40gs. Calculator Tip This trick is particularly helpful if you are working with complex roots. Not only does it make it easier to re-use them it makes it easier to tell at a glance which are real and which complex. 84

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Finding and accessing polynomial roots
The
POLYROOT
function can be used to find roots very quickly, but the results are often difficult to see in the
HOME
view due to the number of decimal places spilling off the edge of the screen, particularly if they
include complex roots.
This can be dealt with easily by storing the results to a matrix.
2
()
=
x
3
3
x
+
3
.
For example, suppose we want to find the roots of
f x
We will use the
POLYROOT
function and store the results into
M1
.
The advantage of this is that you can
now view the roots by changing to the
Matrix Catalog
(
SHIFT 4
) and
pressing
. See page 209 for
more detailed information on matrices.
In addition to this, you can access the roots in the
HOME
view as shown. This method works equally well for
complex roots.
See page 309 for details on finding roots of real and complex
polynomials using the CAS on the hp 40gs.
Calculator Tip
This trick is particularly helpful if you are working with complex roots.
Not only does it make it easier to re-use them it makes it easier to tell at
a glance which are real and which complex.
84