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Differentiation Watch

1. Find the gradient of the curve with equation y=f(x) at the point A where:

f(x)=x^3-3x+2 and A is at (-1,4)

This is what I've done so far but I think it's wrong.

2. (Original post by zed963)
Find the gradient of the curve with equation y=f(x) at the point A where:

f(x)=x^3-3x+2 and A is at (-1,4)

This is what I've done so far but I think it's wrong.

You have gone wrong twice, First with your differentiation. and why have you differentiated twice !!
so
so final answer should be 0
3. (Original post by zed963)
Find the gradient of the curve with equation y=f(x) at the point A where:

f(x)=x^3-3x+2 and A is at (-1,4)

This is what I've done so far but I think it's wrong.

Like the above poster ^ said, EVERY term gets differentiated. So -3x and 2 also get differentiated. Finding out dy/dx means finding an equation that allows you to work out the curve's gradient at a point, which is what you need to do just once. But differentiating a further time means you finding an equation that allows you to determine at a point the rate of change of the gradient. This is not what you want, so you shouldn't have differentiated the extra time.
4. Also I forgot to mention that if you have a curve's equation and you differentiate it, you get dy/dx. Differentiating one more time gives you . Differentiating again gives . Differentiating another time gives you etc...
5. (Original post by krisshP)
Also I forgot to mention that if you have a curve's equation and you differentiate it, you get dy/dx. Differentiating one more time gives you . Differentiating again gives . Differentiating another time gives you etc...

(Original post by brianeverit)
You have gone wrong twice, First with your differentiation. and why have you differentiated twice !!
so
so final answer should be 0
Oh okay,

What I've done now.

6. (Original post by zed963)
Oh okay,

What I've done now.

NO!

The 2 is differentiated to 0. Look

2
=2x^0
=0 X 2x^-1

0 x anything=0

so differentiating 2 gives 0.
7. (Original post by krisshP)
NO!

The 2 is differentiated to 0. Look

2
=2x^0
=0 X 2x^-1

0 x anything=0

so differentiating 2 gives 0.
Oh...

Yes that's true.

8. (Original post by krisshP)
NO!

The 2 is differentiated to 0. Look

2
=2x^0
=0 X 2x^-1

0 x anything=0

so differentiating 2 gives 0.
The two is on its own, why have you included an x?
9. (Original post by zed963)
The two is on its own, why have you included an x?
Because it allows us to see clearly and easily how we can differentiate it.

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