SOLUTION: I could really use some help graphing these two functions: f(x)=7^x f(x)= log3x

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Question 173334: I could really use some help graphing these two functions:
f(x)=7^x
f(x)= log3x

Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
# 1

In order to graph , we need to plot some points:


Note: I'll use "y" in place of f(x)



Let's find the y value when


Start with the given equation


Plug in


Flip the fraction to make the exponent positive.


Square to get


Divide


So when , then


------------------------------------------------------------------


Let's find the y value when


Start with the given equation


Plug in


Flip the fraction to make the exponent positive.


Raise to the first power to get


Divide


So when , then


------------------------------------------------------------------


Let's find the y value when


Start with the given equation


Plug in


Raise to the zeroth power to get



So when , then


------------------------------------------------------------------


Let's find the y value when


Start with the given equation


Plug in


Raise to the first power to get



So when , then


------------------------------------------------------------------


So we have the following values:


xy
-20.02041
-10.14286
01
17




Now let's plot these points





Now draw a curve through those points to graph





Note: the graph does NOT cross or touch the x-axis. It just looks like that since the y values become very small.







# 2



In order to graph , we need to plot some points:


Note: I'll use "y" in place of f(x)


Let's find the y value when


Start with the given equation


Plug in


Use a calculator to evaluate log base 3 of 1 to get 0


So when , then


-----------------------------------------------



Let's find the y value when


Start with the given equation


Plug in


Use a calculator to evaluate log base 3 of 2 to get 0.63093


So when , then


-----------------------------------------------



Let's find the y value when


Start with the given equation


Plug in


Use a calculator to evaluate log base 3 of 3 to get 1


So when , then


-----------------------------------------------



Let's find the y value when


Start with the given equation


Plug in


Use a calculator to evaluate log base 3 of 4 to get 1.26186


So when , then


-----------------------------------------------


Let's find the y value when


Start with the given equation


Plug in


Use a calculator to evaluate log base 3 of 5 to get 1.46497


So when , then


-----------------------------------------------




So we have the following values:


xy
10
20.63093
31
41.26186
51.46497




Now let's plot these points





Now draw a curve through those points to graph



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