The Variable Vx; The Pcoef Function; The Proot Function; The Quotient And Remainder Functions - HP 48gII User Manual

Graphing calculator.

The variable VX

A variable called VX exists in the calculator's {HOME CASDIR} directory that
takes, by default, the value of 'X'.
This is the name of the preferred
independent variable for algebraic and calculus applications. Avoid using
the variable VX in your programs or equations, so as to not get it confused
with the CAS' VX.
For additional information on the CAS variable see
Appendix C in the calculator's user's guide.

The PCOEF function

Given an array containing the roots of a polynomial, the function PCOEF
generates an array containing the coefficients of the corresponding
polynomial.
The coefficients correspond to decreasing order of the
independent variable. For example:
PCOEF([-2 –1 0 1 1 2]) = [1. –1. –5. 5. 4. –4. 0.],
6
5
4
3
2
which represents the polynomial X
-X
-5X
+5X
+4X
-4X.

The PROOT function

Given and array containing the coefficients of a polynomial, in decreasing
order, the function PROOT provides the roots of the polynomial. Example,
2
from X
+5X-6 =0, PROOT([1 –5 6]) = [2. 3.].

The QUOTIENT and REMAINDER functions

The functions QUOTIENT and REMAINDER provide, respectively, the quotient
Q(X) and the remainder R(X), resulting from dividing two polynomials, P
(X)
1
and P
(X). In other words,, they provide the values of Q(X) and R(X) from
2
P
(X)/P
(X) = Q(X) + R(X)/P
(X). For example,
1
2
2
QUOTIENT('X^3-2*X+2', 'X-1') = 'X^2+X-1'
REMAINDER('X^3-2*X+2', 'X-1') = 1.
3
2
Thus, we can write: (X
-2X+2)/(X-1) = X
+X-1 + 1/(X-1).
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