Inverse of a logarithmic function

In summary, the student is having difficulty solving a homework equation. They are stuck after solving one step and are not sure if they have solved the equation correctly. They are looking for help and are using hints from others, but are not able to solve the equation on their own.
  • #1
togame
18
0

Homework Statement


Greetings everyone! I am having problems getting started with this question, which asks:

Find the inverse of [itex]y = \frac{3-4e^x}{6-10e^x}[/itex]

Homework Equations


The Attempt at a Solution



I'm usually pretty good with these kinds of problems, but for some reason I seem to be unable to completely grasp this one. I can get one step and I'm not even sure that it's right.
[tex]y(6-10e^x) = 3-4e^x[/tex]

After that I'm stuck. I can't seem to isolate e. Either I'm misunderstanding the law of logarithms or I just don't know. If someone could point me in the right direction, it would be greatly appreciated.
 
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  • #2
Try using this :

[itex] log(y) = log \left(\frac{3-4e^x}{6-10e^x}\right)[/itex]
 
  • #3
So my next step would be to simplify the right side using log laws, yes?
[tex]log(y)=log(3-4e^x)-log(6-10e^x)[/tex]

This seems wrong but it's the only way I know.
 
  • #4
rollcast said:
Try using this :

[itex] log(y) = log \left(\frac{3-4e^x}{6-10e^x}\right)[/itex]
I don't see that this is a helpful hint.
 
  • #5
togame said:

Homework Statement


Greetings everyone! I am having problems getting started with this question, which asks:

Find the inverse of [itex]y = \frac{3-4e^x}{6-10e^x}[/itex]

Homework Equations





The Attempt at a Solution



I'm usually pretty good with these kinds of problems, but for some reason I seem to be unable to completely grasp this one. I can get one step and I'm not even sure that it's right.
[tex]y(6-10e^x) = 3-4e^x[/tex]


After that I'm stuck. I can't seem to isolate e. Either I'm misunderstanding the law of logarithms or I just don't know. If someone could point me in the right direction, it would be greatly appreciated.
Multiply out the left side, and then move all the terms with ex to the left side, and all the other terms to the right side. Finally, factor out ex and isolate it.
 
  • #6
Ah I see it now. Don't know how I missed that before. Thanks for the help mark!
 

What is the definition of the inverse of a logarithmic function?

The inverse of a logarithmic function is a function that "undoes" the original logarithmic function. It is a function that takes the output of the original logarithmic function and gives back the input. In other words, if y is the output of the original logarithmic function, then the input of the inverse function will be y.

How do you find the inverse of a logarithmic function?

To find the inverse of a logarithmic function, switch the roles of x and y in the equation and solve for y. The resulting equation will be the inverse function.

Why is it important to find the inverse of a logarithmic function?

Finding the inverse of a logarithmic function is important because it allows us to solve equations involving logarithmic functions. It also helps us understand the relationship between a logarithmic function and its inverse, and how they "cancel" each other out.

What is the domain and range of the inverse of a logarithmic function?

The domain of the inverse of a logarithmic function is the range of the original logarithmic function. Similarly, the range of the inverse function is the domain of the original logarithmic function. In both cases, the domain and range are restricted to values that make the function one-to-one.

Can all logarithmic functions have an inverse?

No, not all logarithmic functions have an inverse. For a function to have an inverse, it must be one-to-one, meaning that each output has a unique input. Logarithmic functions that have a base of 1 or a negative base will not have an inverse function.

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