Fractions, The peval function, The simp2 function – HP 49g+ User Manual

Page 88

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Note: you could get the latter result by using PARTFRAC:

PARTFRAC(‘(X^3-2*X+2)/(X-1)’) = ‘X^2+X-1 + 1/(X-1)’.

The PEVAL function

The functions PEVAL (Polynomial EVALuation) can be used to evaluate a
polynomial

p(x) = a

n

x

n

+a

n-1

x

n-1

+ …+ a

2

x

2

+a

1

x+ a

0

,

given an array of coefficients [a

n

, a

n-1

, … a

2

, a

1

, a

0

] and a value of x

0

. The

result is the evaluation p(x

0

). Function PEVAL is not available in the

ARITHMETIC menu, it must be accessed from the function catalog

(‚N).

Example: PEVAL([1,5,6,1],5) = 281.


Additional applications of polynomial functions are presented in Chapter 5 in
the calculator’s User’s Guide.

Fractions

Fractions can be expanded and factored by using functions EXPAND and
FACTOR, from the ALG menu (‚×). For example:

EXPAND(‘(1+X)^3/((X-1)(X+3))’) = ‘(X^3+3*X^2+3*X+1)/(X^2+2*X-3)’
EXPAND(‘(X^2*(X+Y)/(2*X-X^2)^2’) = ‘(X+Y)/(X^2-4*X+4)’

FACTOR(‘(3*X^3-2*X^2)/(X^2-5*X+6)’) = ‘X^2*(3*X-2)/((X-2)*(X-3))’
FACTOR(‘(X^3-9*X)/(X^2-5*X+6)’ ) = ‘X*(X+3)/(X-2)’


The SIMP2 function

Function SIMP2 takes as arguments two numbers or polynomials, representing
the numerator and denominator of a rational fraction, and returns the
simplified numerator and denominator. For example:

SIMP2(‘X^3-1’,’X^2-4*X+3’) = { ‘X^2+X+1’,‘X-3’}


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