Welcome :: Homework Help and Answers :: Mathskey.com

Recent Visits

    
Welcome to Mathskey.com Question & Answers Community. Ask any math/science homework question and receive answers from other members of the community.

13,435 questions

17,804 answers

1,438 comments

777,271 users

Math question, please help?

0 votes

"Graph the function and identify the vertical asymptote. 
y = 1/(x + 2) + 4" 

asked May 10, 2014 in PRECALCULUS by anonymous

1 Answer

0 votes

The rational function is y = 1/(x + 2) + 4.

It can be written as y  = [1 + 4(x + 2)] / (x + 2) = (4x + 9) / (x + 2).

The graph of rational functions can be recognised by the fact two or more parts.

1). y = (4x + 9) / (x + 2)

To find  y - intercept  x = 0 in the rational function.

y = (4(0) + 9) / (0 + 2)

= 9/2.

2). To find x - intercept, let the numarator = 0

4x + 9 = 0

x  = - 9/4.

3)Vertical asymptotes are found  by solving denominator = 0

x + 2 = 0

x = - 2.

Vertical asymptotes is x = - 2.

4).Degree of the numarator = 1 and the degree of denominator = 1.

If the degreeof numerator = degree of denominator, then horizontal asymptote = ratio of leading coefficients.

Therfore, the line y = 4, is the horizontal asymptote.

Now, pick few more x - values, compute the corresponding y  values and flat few more points.

x

y = (4x + 9) / (x + 2)

(x , y )

- 6

y = (4(- 6) + 9) / (- 6 + 2) = (- 24 + 9)/- 4 = - 15/- 4 = 15/4 (- 6, 15/4)

- 5

y = (4(- 5) + 9) / (- 5 + 2) = (- 20 + 9)/- 3 = - 11/- 3 = 11/3 (- 5, 11/3)

- 4

y = (4(- 4) + 9) / (- 4 + 2) = (- 16 + 9)/- 2 = - 7/- 2 = 7/2 (- 4, 7/2)
- 3

y = (4(- 3) + 9) / (- 3 + 2) = (- 12 + 9)/- 1 = - 3/- 1 = 3

(- 3, 3)
- 2

y = (4(- 2) + 9) / (- 2 + 2) = (- 8 + 9)/0 = 1/0 = undefined

undefined
- 1

y = (4(- 1) + 9) / (- 1 + 2) = (- 4 + 9)/1 = 5/1 = 5

(- 1, 5)
0

y = (4(0) + 9) / (0 + 2) = 9/2

(0, 9/2)
1

y = (4(1) + 9) / (1 + 2) = (4 + 9)/3 = 13/3 

(1, 13/3)
2

y = (4(2) + 9) / (2 + 2) = (8 + 9)/4 = 17/4

(2, 17/4)
 

Graph :

1) Draw the coordinate plane.

2) Next dash the horizontal and vertical asympototes

3) Plot the x intercept and coordinate pairs found in the table..

4) Connect the plotted points .

When you draw your graph, use smmoth curves complete the graph.

 

answered Aug 28, 2014 by david Expert
edited Aug 28, 2014 by bradely

Related questions

asked Jul 23, 2014 in PRECALCULUS by anonymous
asked Jul 23, 2014 in PRECALCULUS by anonymous
asked Jul 22, 2014 in PRECALCULUS by anonymous
asked Apr 26, 2015 in CALCULUS by anonymous
asked Oct 30, 2014 in ALGEBRA 2 by anonymous
asked Aug 5, 2014 in PRECALCULUS by anonymous
...