Finding the Inverse of a Function: g(x) = x/3 - 5

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In summary, the inverse of the function g(x) = x/3 -5 is 3x + 15 = y. This can be verified by forming a composite function of g(x) and its inverse, which results in x. Therefore, the inverse found is correct.
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Nelo
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Homework Statement



Inverse of g(x) = x/3 -5


Homework Equations





The Attempt at a Solution



The inverse of the function

g(x) = x/3 -5
x= y/3 -5
x +5 = y/ 3
3x + 15 = y

Is this correct?

Or is it x+5 /3 ?
 
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  • #2
Your original looks correct.

If you have a graphic calculator, graph them both, the inverse should be a 90* rotation from the original, since you essentially have the same function with swapped axis.
 
  • #3
If you want to check to see if the inverse function you found is correct, all you need to do is form a composite function of the original function and its inverse. If the composite function of g(x) and g-1(x) is equal to x, then the inverse you found is correct.

[itex]g[g^{-1}(x)]=(\frac{3x+15}{3})-5=(x+5)-5=x[/itex]

Yes, the inverse you found is correct.
 

FAQ: Finding the Inverse of a Function: g(x) = x/3 - 5

What is the inverse of a function?

The inverse of a function is a new function that reverses the original function's input and output. In other words, if the original function takes an input x and produces an output y, the inverse function takes y as an input and produces x as an output.

How do you find the inverse of a function?

To find the inverse of a function, you can follow these steps:

  1. Replace the function notation with y.
  2. Swap the x and y variables.
  3. Solve for y.
  4. Replace y with the inverse function notation, g-1(x).

What is the inverse of g(x) = x/3 - 5?

The inverse of g(x) = x/3 - 5 is g-1(x) = 3x + 15. To find the inverse, we follow the steps outlined in the previous answer.

How do you check if a function and its inverse are correct?

To check if a function and its inverse are correct, you can use the composition method. This involves plugging the inverse function into the original function and vice versa. If the output of the composition is x for both cases, then the functions are inverses of each other.

Can every function have an inverse?

No, not every function has an inverse. A function must be one-to-one (each input has a unique output) and onto (every output has at least one corresponding input) to have an inverse. If a function fails either of these criteria, it does not have an inverse.

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