- #1

- 157

- 0

## Homework Statement

y=2√x-x

## The Attempt at a Solution

First derivative:

-2x

^{-2}-1

Second derivative:

4x

^{-3}

4x

^{-3}=0

No solutions?

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- Thread starter phillyolly
- Start date

- #1

- 157

- 0

y=2√x-x

First derivative:

-2x

Second derivative:

4x

4x

No solutions?

- #2

Mentallic

Homework Helper

- 3,798

- 94

So [tex]y=2x^{1/2}-x[/tex]

Then [tex]\frac{dy}{dx}=x^{-1/2}-1[/tex]

Which isn't what you got.

- #3

Mentallic

Homework Helper

- 3,798

- 94

- #4

- 157

- 0

So the first derivative is

(x

I take a second derivative to find an inflection point.

y''=-1/2x

What does it mean?...

- #5

- 867

- 0

x = 0 isn't in the domain because you would have 0 in the denominator, but that's not really important. This function y'' is never 0, it will never touch the x-axis, so y does not have an inflection point.

- #6

- 157

- 0

x = 0 isn't in the domain because you would have 0 in the denominator, but that's not really important. This function y'' is never 0, it will never touch the x-axis, so y does not have an inflection point.

Yes, I see I was wrong, I cannot have x=0 as a solution in this function.

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