Inverse of exponential function

In summary, you are having trouble with the syntax of your equation in Maple. You should check to see if you are missing any parentheses or brackets, and if so, correct them. Additionally, you may also want to simplify the equation as much as possible.
  • #1
mark187
3
0

Homework Statement



Give the inverse of this function

N=f(L)=1816-8L

The answer has to be filled in in Maple

Homework Equations





The Attempt at a Solution



N=1816-8L

16-8L=ln(N)/ln(18)

-8L=(ln(N)/ln(18))-16

L=-ln(N)/(8*ln(18))+2

Is this correct?
When i fill this in in maple it's incorrect.
I've really no clue why it is wrong.
 
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  • #2
L=-ln(N)/(8*ln(18))+2 is the same function as the original. Choose L the independent variable and N the dependent one. (Just exchange L and N).

ehild
 
  • #3
Yes it's correct. What are you typing into maple exactly? Your syntax is probably slightly off.

edit: Sorry I didn't notice that you forgot to swap your variables.
 
  • #4
thanks! It's also mentioned that it should be simplified as much as possible.

Does that mean that the 8*LN(18) could be simplified to 8*LN(2*9) and more?
 
  • #5
It's as simple as it can get, unless you believe [itex]\ln{\frac{1}{x}}[/itex] is more simple than [itex]-\ln{x}[/itex] you shouldn't be changing anything.

[itex]\ln{18}[/itex] is definitely more desirable than [itex]\ln{9\cdot2}[/itex] :wink:
 
  • #6
mark187 said:

Homework Statement



Give the inverse of this function

N=f(L)=1816-8L

The answer has to be filled in in Maple

Homework Equations





The Attempt at a Solution



N=1816-8L

16-8L=ln(N)/ln(18)

-8L=(ln(N)/ln(18))-16

L=-ln(N)/(8*ln(18))+2

Is this correct?
When i fill this in in maple it's incorrect.
I've really no clue why it is wrong.

When I let Maple solve the equation for L it gives me exactly what you wrote. Why do you think Maple thinks it is incorrectÉ What type of error message are you receivingÉ

That annoying É is actually a question mark, but when I type it in it gives me that accented E; that only seems to happen when I access this website through Google Chrome!

RGV
 
  • #7
Ray Vickson said:
When I let Maple solve the equation for L it gives me exactly what you wrote. Why do you think Maple thinks it is incorrectÉ What type of error message are you receivingÉ

That annoying É is actually a question mark, but when I type it in it gives me that accented E; that only seems to happen when I access this website through Google Chrome!

RGV

Well, this assignment was given in a little online test.
The point is, that i can't see why the answer was wrong.
I have 2 chances, so for the second change i will try to swap the variables.
 

What is an inverse of an exponential function?

An inverse of an exponential function is a function that "undoes" the original exponential function. It takes the output of the original function and returns the input that was used to produce that output.

How do you find the inverse of an exponential function?

To find the inverse of an exponential function, you can use algebraic methods such as switching the x and y variables and solving for y. Alternatively, you can use graphical methods by reflecting the original exponential function over the line y=x.

What is the domain and range of an inverse exponential function?

The domain of an inverse exponential function is the range of the original exponential function, and the range of an inverse exponential function is the domain of the original exponential function.

Can all exponential functions have an inverse?

No, not all exponential functions have an inverse. For an exponential function to have an inverse, it must pass the horizontal line test, meaning that every horizontal line intersects the function at most once.

What is the relationship between exponential and logarithmic functions?

Exponential and logarithmic functions are inverse functions of each other. This means that the inverse of an exponential function is a logarithmic function, and vice versa. They are used to model real-life situations such as population growth and decay, interest rates, and radioactive decay.

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