SOLUTION: Find an equation of a rational function f that satisfies the given conditions. vertical asymptotes: x = −3, x = 0 horizontal asymptote: y = 0 x-intercept: 3; f(4) = 1

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Question 1113797: Find an equation of a rational function f that satisfies the given conditions.
vertical asymptotes: x = −3, x = 0
horizontal asymptote: y = 0
x-intercept: 3; f(4) = 1

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


(1) vertical asymptotes: x = −3, x = 0

Vertical asymptotes (values of x where the function is undefined -- i.e., has no value) are caused by factors in the denominator that are equal to 0. If there are asymptotes at x=-3 and x=0, then there are factors of (x+3) and x in the denominator.
a%2F%28%28x%2B3%29%28x%29%29

(2) horizontal asymptote: y = 0

The horizontal asymptote is 0 if the degree of the numerator is less than the degree of the numerator. We'll come back to this one....

(3) x-intercept: 3

An x-intercept (where the function value is 0) is caused by a factor in the numerator that is equal to 0. If there is an x-intercept at x=3, there must be a factor of (x-3) in the numerator.
a%28x-3%29%2F%28%28x%2B3%29%28x%29%29

Note that the degree of the numerator at this point is less than the degree of the denominator; so the condition for having a horizontal asymptote of y=0 is satisfied. So we have all the factors of our rational function that contain variables; we now need to find the constant factor.

(4) f(4) = 1

a%284-3%29%2F%28%284%2B3%29%284%29%29+=+1
a%2F28+=+1
a+=+28

Our rational function is
28%28x-3%29%2F%28%28x%2B3%29%28x%29%29

A graph...

graph%28400%2C400%2C-10%2C5%2C-50%2C150%2C28%28x-3%29%2F%28%28x%2B3%29%28x%29%29%29