How do you sketch #y = x/(x(x-2)#?

1 Answer
Dec 4, 2016

Eliminating the #x# in the numerator and in the denominator gives us a hole at #x = 0#.

There is a vertical asymptote at #x= 2# and a horizontal asymptote at #y = 0#.

The intercepts are:

#y = 1/(0 - 2)#

#y = -1/2#

AND

#0 = 1/(x - 2)#

#0 = 1#; there are no x-intercepts.

#:.#There is a y-intercept at #(0, -1/2)#.

The end behaviour of the function can be found by considering some test points.

Let #x= -100# and #x = -1000#

For #x= -100#

#y = 1/(x- 2)#

#y= 1/(-100 - 2)#

#y ~=-0.0098#

For #x = -1000#

#y = 1/(-1002)#

#y = -0.000998#

As you can see, these numbers are trending towards the horizontal asymptote at #y= 0#.

We do the same near the asymptote.

Let #x = 1.75# and #x= 1.99#.

For #x = 1.75#

#y = 1/(x- 2)#

#y = 1/(1.75 - 2)#

#y= -4

For #x = 1.99#

#y = 1/(x- 2)#

#y = 1/(1.99 - 2)#

#y = -100#

So, as #x# approaches #2# from the left side, #y# approaches negative infinity. Doing the same process for the right side, you should get the as #x# approaches #2# from the right side, #y# approaches positive infinity.

We repeat the process of checking end behaviour at the right side of the function as #x# approaches positive infinity, to get that #y# tends to #y =0#.

The final graph should look like the following, with a hole at #x= 0#.

enter image source here

Hopefully this helps!