Question #911b5

2 Answers
Dec 15, 2017

#(-oo , oo)#

Explanation:

#f(x)=(x^2-5x+4)/(x^2-3x+2)#

Vertical asymptotes occur where the function is undefined. In this case where the denominator is #0#

#x^2-3x+2=0#

#(x-1)(x-2)=0=>x=1 and x=2#

If we factor the numerator:

#x^2-5x+4#

#(x-4)(x-1)#

When we view the function like this:

#f(x)=((x-4)(x-1))/((x-1)(x-2))#

We notice that we can cancel the #(x-1)# factors. This is known as removing the discontinuity. So we now know that the vertical line #x=2# is an asymptote, and #x=1# is just a point discontinuity.

as #x->2^-# , #(x^2-5x+4)/(x^2-3x+2)->oo#

as #x->2^+# , #(x^2-5x+4)/(x^2-3x+2)->-oo#

So range of function is:

#(-oo , oo)#

Dec 15, 2017

The range is #y in RR-{1}#

Explanation:

We are given

#y=(x^2-5x+4)/(x^2-3x+2)=((x-4)cancel(x-1))/((x-2)cancel(x-1))#

Rearranging the function

#y(x-2)=(x-4)#

#xy-2y=x-4#

#xy-x=2y-4#

#x(y-1)=2(y-2)#

#x=2(y-2)/(y-1)#

#x# will have solutions iff the denominator is #!=0#

Therefore,

#y-1!=0#

#y!=1#

The range is #y in RR-{1}#
graph{(x-4)/(x-2) [-11.25, 11.245, -5.63, 5.62]}