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1 Answer
Oct 20, 2017

a y=0, x=-2 and x=1.
b Local maxima is f(4)=1/9 and local minima is f(0)=1.
c x-intersept is (2,0) and y-intersept is (0,1).
d,e See below.

Explanation:

f(x)=(x-2)/(x^2+x-2)=(x-2)/((x+2)(x-1))

a. When x goes to infinity, lim_(x->oo)f(x)=0 andlim_(x->-oo)f(x)=0 . This means that x-axis is one of the asymptotes.
In addition, f(x) is not defined at x=-2,1. Therefore x=-2 and x=1 are also asymptotes.

b
First, differentiate f(x).
f'(x)=((x-2)'(x^2+x-2)-(x-2)(x^2+x-2)')/(x^2+x-2)^2
=(1*(x^2+x-2)-(x-2)(2x+1))/(x^2+x-2)^2
=-(x^2-4x)/(x^2+x-2)^2

Solving f'(x)=0 leads to x=0,4 and it indicates that f(0)=1 and f(4)=1/9 are local maxima or minima.

When x<-2, -2< x< 0 and x>4, f(x) is monotonically decreasing because f'(x)=-(x(x-4))/(x^2+x-2)^2 is negative for this domain.
Likewise, f(x) is monotonically increasing when 0< x< 1 , 1< x< 4.
Thus, f(0) is the local minima and f(4) is the local maxima.

c
Substitute x=0 and y=0 to the formula and the intersepts are obvious. (2,0),(0,1).

d
graph{(x-2)/(x^2+x-2) [-10, 10, -5, 5]}

e
Draw the line y=p on the graph and find when y=f(x) and y=p cross at two distinct point. The answer is p< 0, 0< p< 1/9 and 1< p.