# help graphing 3 functions

• Feb 27th 2008, 03:59 AM
mt_lapin
help graphing 3 functions
Graph these functions.

$\displaystyle f(x)=3^{x}$

$\displaystyle f(x)=-3(3)^{x}$

$\displaystyle f(x)=20\left(\frac{1}{4}\right)^{x}$

I know graphs don't have to be perfect. But how would these look....if there was a table for each function with x values of -3, -2,-1, 0, 1, 2, 3 ?

The tables, respectively, would be:

x/ f(x)
-3/ (1/27)
-2/ (1/9)
-1/ (1/3)
0/ 1
1/ 3
2/ 9
3/ 27

x/ f(x)
-3/ (-1/9)
-2/ (-1/3)
-1/ -1
0/ -3
1/ -9
2/ -27
3/ -81

x/ f(x)
-3/ 1280
-2/ 320
-1/ 80
0/ 20
1/ 5
2/ (5/4)
3/ (5/16)
• Feb 27th 2008, 05:24 AM
kalagota
do you know the graph of $\displaystyle e^x$?
if does, then the graph of $\displaystyle a^x$ for $\displaystyle a>1$ looks like the graph of $\displaystyle e^x$.. (see graph1)
if you multiply a negative number from that $\displaystyle a^x$ for $\displaystyle a>1$, the graph is reflected about the x-axis.. (see graph2)

however, the graph of $\displaystyle a^x$ for $\displaystyle 0<a<1$ is a reflection about the y-axis.. (see graph3 and graph4)