The quot and remainder functions, The epsx0 function and the cas variable eps, The peval function – HP 48gII User Manual

Page 194

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The QUOT and REMAINDER functions
The functions QUOT and REMAINDER provide, respectively, the quotient Q(X)
and the remainder R(X), resulting from dividing two polynomials, P

1

(X) and

P

2

(X). In other words, they provide the values of Q(X) and R(X) from

P

1

(X)/P

2

(X) = Q(X) + R(X)/P

2

(X). For example,

QUOT(X^3-2*X+2, X-1) = X^2+X-1

REMAINDER(X^3-2*X+2, X-1) = 1.


Thus, we can write: (X

3

-2X+2)/(X-1) = X

2

+X-1 + 1/(X-1).


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

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


The EPSX0 function and the CAS variable EPS
The variable ε (epsilon) is typically used in mathematical textbooks to
represent a very small number. The calculator’s CAS creates a variable EPS,
with default value 0.0000000001 = 10

-10

, when you use the EPSX0 function.

You can change this value, once created, if you prefer a different value for
EPS. The function EPSX0, when applied to a polynomial, will replace all
coefficients whose absolute value is less than EPS with a zero. Function
EPSX0 is not available in the ARITHMETIC menu, it must be accessed from the
function catalog (N). Example:

EPSX0(‘X^3-1.2E-12*X^2+1.2E-6*X+6.2E-11)=
‘X^3-0*X^2+.0000012*X+0’.

With µ: ‘X^3+.0000012*X’.

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.

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