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if f(x)=x the inverse of f is ??? watch

1. What would I do?

f-1(x) = x???
2. inverse f(x) also equals to x
3. (Original post by kprime2)
inverse f(x) also equals to x
Why is this, I thought it was just 1.

Or is it that if you interchange y and x you get f(x) = x still.
4. (Original post by Moordland)
Why is this, I thought it was just 1.

Or is it that if you interchange y and x you get f(x) = x still.
The inverse function is a reflection of the function in the line y=x. It probably doesn't answer that question but draw f(x) on a graph and try to reflect it in the line y=x, you'll see why the inverse is the same.
5. (Original post by CheetahCurtis)
The inverse function is a reflection of the function in the line y=x. It probably doesn't answer that question but draw f(x) on a graph and try to reflect it in the line y=x, you'll see why the inverse is the same.
omg ofc ty
6. (Original post by Moordland)
Why is this, I thought it was just 1.

Or is it that if you interchange y and x you get f(x) = x still.
Well yeah.
If you imagine the line y=x, whatever you sub in for x that's what you get for y as you probably already understand. If you reflect y=x into the line y=x there is no change.
7. (Original post by kprime2)
Well yeah.
If you imagine the line y=x, whatever you sub in for x that's what you get for y as you probably already understand. If you reflect y=x into the line y=x there is no change.
Yes of course thank you!
8. (Original post by Moordland)
Why is this, I thought it was just 1.

Or is it that if you interchange y and x you get f(x) = x still.
You seem to understand now but I'll explain this in a different way anyway.

Think of a function as having an input and an output.

f(x) = x

For this function. whatever you put into it is the same as what you get out.

An inverse function takes you back from the output to the input. But since the input and output are the same, the function f(x) = x will work as an inverse function.

E.g. Using the number '2' as input to f(x) = x:

f(2) = 2

The output is 2. Then using f(x) = x again with this output as input:

f(2) = 2

Which gives us the original input.
9. (Original post by notnek)
You seem to understand now but I'll explain this in a different way anyway.

Think of a function as having an input and an output.

f(x) = x

For this function. whatever you put into it is the same as what you get out.

An inverse function takes you back from the output to the input. But since the input and output are the same, the function f(x) = x will work as an inverse function.

E.g. Using the number '2' as input to f(x) = x:

f(2) = 2

The output is 2. Then using f(x) = x again with this output as input:

f(2) = 2

Which gives us the original input.
This is a great explanation.

Thank you.

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Updated: August 24, 2015
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