# Homework Help: Find the derivitive of the function? Help

1. May 30, 2012

### ForeverMo

Find the derivitive of the function? Help:)

1. The problem statement, all variables and given/known data
g(x)=√x^2-2x+1

2. Relevant equations

3. The attempt at a solution
I rewrote the problem as g(x)=(x^2-2x+1)^1/2
Then..
1/2(x^2-2x+1)^-1/2(2x-2)(2)
But I got it wrong at that step whenever I wrote the "2"
Can you help?

2. May 30, 2012

### Staff: Mentor

Re: Find the derivitive of the function? Help:)

You don't need that final 2. What you have is u1/2, where u = x2 - 2x + 1.
d/dx(u1/2) = (1/2)u-1/2 * du/dx

3. May 30, 2012

### ForeverMo

Re: Find the derivitive of the function? Help:)

Ok, I understand.. But for some reason I was wanting to write the derivitave of 2x, which is 2 right??

4. May 30, 2012

### Staff: Mentor

Re: Find the derivitive of the function? Help:)

du/dx = 2x - 2

5. May 30, 2012

### ForeverMo

Re: Find the derivitive of the function? Help:)

Ohhhh ohk I knew that..Thanks Alot :D
Could you please take a look at my other post?

6. May 30, 2012

### HallsofIvy

Re: Find the derivitive of the function? Help:)

Actually, $y= (x^2- 2x+ 1)^{1/2}= ((x- 1)^2)^{1/2}= |x- 1|$
That has derivative -1 if x< 1, 1 if x> 1 and is not differentiable at x= 1.

That is the same as $y'= (1/2)(x^2- x+ 1)^{-1/2}(2x- 2)= (x-1)/|x- 1|$.