Question 132970: Can you explain me how do I find the asymptotes of the functions f(x)=3^x and
g(x) = log5(2x).
Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website! 
First, is not an asymptote because 
and . changes smoothly on either side of 
and , so the plot is
. . 
.989 . . -0.01
1 . . 0
1.011 . . 0.01
The smooth changes in both and means there is
no asyptote
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As becomes infinitely large in the + direction, 
becomes larger at an even greater rate without any bounds.
As becomes larger in the negative direction, however,
gets closer and closer to , but never
becomes negative. There is no way can possibly be negative.
is the definition of the x-axis, so the negative
x-axis is an asyptote
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g(x) = log5(2x)
If I say , I can rewrite the equation as

Is an asymptote? If , approaches
negative infinity. There is no way that can ever be
negative since can never be negative. is the
definition of the y-axis, so the y-axis is an asymptote
When becomes very large in the + direction, 
also becomes very large, just not at as fast a rate.
I'll plot the curves

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