Graph y = 3^(x+1) - 2: Do I make an (x,y) table?

G

Guest

Guest
How do I graph y = 3^(x+1) - 2?????

Do I make an (x,y) table like in algebra 1?
 
Re: Graph y = 3^(x+1) - 2

interval said:
Do I make an (x,y) table like in algebra 1?
Click to expand...
Yes. You'll need plenty of points, though, since this isn't just a simple straight line.

Eliz.
 
ok

Good. About how many points would you say I need to sketch this weird function?
 
interval said:
About how many points would you say I need to sketch this weird function?
Click to expand...
That will vary with the points you pick, and how solid an understanding you have of basic exponential-function behavior. For instance, would it do you much good to plot a point for x = -10? For x = 10? Why or why not? And so forth.

In general, plot points until you're confident of the shape of the graph.

Eliz.
 
ok

Let's say I am told to graph the function that we are talking in the interval [-8, 8].

Does it mean I must graph every point in that interval or would it be okay with just a few points from that interval?
 
Plotting all of the points would probably be over-kill, especially since many of them will have almost indistiguishable y-values. But there is no magic number. You need to plot however many points you need to feel confident in your graph. If you've got a good feel for exponential functions, then three or four would probably do. If you're just starting out, and especially if you're having difficulty getting the right graph, then more points would probably be better.

Eliz.
 
interval said:
How do I graph y = 3^(x+1) - 2?????

Do I make an (x,y) table like in algebra 1?
Click to expand...

You certainly COULD make an (x, y) table....that should always work provided you use a sufficient number of points to give you a good idea of what the graph looks like.

That said, I believe you're being asked to consider the transformation of a basic function. In one of your other posts, you indicated that you could graph draw the graph of
y = 3<SUP>x</SUP>

The graph of
y = 3<SUP>x + 1</SUP> - 2

is the graph of y = 3<SUP>x</SUP>, moved 1 unit to the left and 2 units down. Take some of the points you KNOW are on the graph of y = 3<SUP>x</SUP>, like (0, 1), (1, 3), (2, 9), (-1, 1/3) and so forth. Move each of those points 1 unit left and 2 units down....and sketch the graph.

For a "lesson" on the basics of transformation of functions, try this:
http://www.purplemath.com/modules/fcntrans.htm

There are additional lessons which deal with this topic at purplemath; you might find it beneficial to study the others.

I hope this helps you.
 
ok

Mrspi and Stapel,

I thank you both for the great tips and comments regarding my functions. Graphing is something I enjoy in the world of math.
 
You must log in or register to reply here.
Top