SOLUTION: For the function: (x^3+2x^2-4x-8)/2x^2-8 a) Find the domain of the function, and discuss the behavior of f near any excluded x ­values. b) Identify all intercepts c) Find all

Algebra ->  Functions -> SOLUTION: For the function: (x^3+2x^2-4x-8)/2x^2-8 a) Find the domain of the function, and discuss the behavior of f near any excluded x ­values. b) Identify all intercepts c) Find all       Log On


   



Question 1027061: For the function: (x^3+2x^2-4x-8)/2x^2-8
a) Find the domain of the function, and discuss the behavior of f near any excluded x ­values.
b) Identify all intercepts
c) Find all vertical, horizontal, and slant asymptotes of the graph of the function.

Found 2 solutions by robertb, KMST:
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
Is the function %28x%5E3%2B2x%5E2-4x-8%29%2F2x%5E2-8+ or %28x%5E3%2B2x%5E2-4x-8%29%2F%282x%5E2-8%29??

Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
I assume you meant
f%28x%29=%28x%5E3%2B2x%5E2-4x-8%29%2F%282x%5E2-8%29 .
The numerator and denominator of that rational function can be factored.
.
When x%5E2-4=0<--->system%7Bx=-2%2C%22or%22%2Cx=2%29 the denominator is zero,
and the function has no defined value.

a) So, the values system%7Bx=-2%2C%22and%22%2Cx=2%29 are excluded from the domain of the function.
The function can be simplified as
f%28x%29=%28x%2B2%29%2F2=%281%2F2%29x%2B1 for system%7Bx%3C%3E-2%2C%22and%22%2Cx%3C%3E2%29 .
The graph of f%28x%29 is a straight line with two holes,
and the behavior of f%28x%29 near the excluded values (and everywhere else in its domain)
is just like the behavior of g%28x%29=%28x%2B2%29%2F2=%281%2F2%29x%2B1 .
In other words, lim%28x-%3E-2%2Cf%28x%29%29=%28-2%2B2%29%2F2=0 and lim%28x-%3E2%2Cf%28x%29%29=%282%2B2%29%2F2=2 .

b) The y-intercept of f%28x%29 is f%280%29=%280%2B2%29%2F2=2%2F2=1 ,
or the point (0,1) .
f%28x%29 is never zero, because where the function exists
it is equal to g%28x%29=%28x%2B2%29%2F2 ,
and g%28x%29=0 only for x=-2 which is not part of the domain of f%28x%29 .
So, there is no x-intercept. The graph of function does not intersect the x-axis; it jumps over it.

c) Since everywhere in its domain f%28x%29=%281%2F2%29x%2B1 ,
the line y=%281%2F2%29x%2B1 could be considered the slant asymptote. There is no other asymptote.