QUESTIONS - FUNCTIONS

QUESTIONS - ANSWERS - FUNCTIONS
On 11/28/06, Anonymous wrote:
> Anonymous has left a new comment on your post "QUESTIONS - POLYNOMIALS":
>
> If you have the time to lend some help, I'd be grateful. 1) Determine the
> domain of the following rational function. Give the answer in set notation
> and in interval notation. f(x) = 15 / (x + 10)
DOMAIN ALL THE VALUES, THE INDEPENDENT VARIABLE X CAN TAKE , WITHOUT
MAKING THE FUNCTION MEANING LESS.
DENOMINATOR X+10 SHOULD NOT BE ZERO AS IT WILL MAKE THE FUNCTION
MEANING LESS.
HENCE DOMAIN IS ALL REAL VALUES OF X EXCEPT X=-10
IN SET NOTATION
(- INFINITY,-10)U(-10,+INFINITY)


2) What are the vertical
> asymptotes of the following rational function? f(x) = (x+3) / (x2 + x –20) = Y SAY
VERTICAL ASYMPTOTES ARE THOSE VALUES OF X WHICH MAKE THE FUNCTION TEND
TO INFINITY.
Y = (X+3)/(X^2+5X-4X-20)=(X+3)/[X(X+5)-4(X+5)] = (X+3)/[(X+5)(X-4)]
HENCE AS X TENDS 4 AND -5 ,Y TENDS TO INFINITY.
X-4 =0 ...OR....X=4...AND
X+5=0...OR.....X=-5 ARE THE 2 VERTICAL ASYMPTOTES