
Bradford T. answered 08/22/21
Retired Engineer / Upper level math instructor
f(x) = x2/(x2-1) = x2/((x+1)(x-1))
a) The vertical asymptotes are found my setting the denominator to zero and solving for x.
(x+1)(x-1)=0
The horizontal asymptotes are found by taking the lim x→∞.
b)
f '(x) = (2x(x2-1)-x2(2x))/(x2-1)2 = (2x3-2x -2x3)/(x2-1)2 = -2x/(x2-1)2
The critical points are found by setting f'(x) = 0 and solving for x and where the derivative doesn't exist.
-2x/(x2-1)2=0
-2x=0
x=0
Derivative doesn't exist at (x2-1)2=0 ---> x = ±1
Taking the 2nd derivative test.
f "(x) = 2(3x2+1)/(x2-1)3
f "(0) = -2 <0 then (0,0) is a maximum
f "(±1) undefined