Can someone help me with this differentiation question?

Calculate f’(4) given that f(x) = (2x^2 - 2) / root x

Sorry I couldn’t upload an image so it looks even more confusing written out. I thought the root x would have moved up to become -2x^-1/2

But all I know is the answer is 49/8 and I have no clue how to get that!! I thought differentiation was easy so I’m stressing

Calculate f’(4) given that f(x) = (2x^2 - 2) / root x

Sorry I couldn’t upload an image so it looks even more confusing written out. I thought the root x would have moved up to become -2x^-1/2

But all I know is the answer is 49/8 and I have no clue how to get that!! I thought differentiation was easy so I’m stressing

Original post by RaggaMuffin49

Can someone help me with this differentiation question?

Calculate f’(4) given that f(x) = (2x^2 - 2) / root x

Sorry I couldn’t upload an image so it looks even more confusing written out. I thought the root x would have moved up to become -2x^-1/2

But all I know is the answer is 49/8 and I have no clue how to get that!! I thought differentiation was easy so I’m stressing

Calculate f’(4) given that f(x) = (2x^2 - 2) / root x

Sorry I couldn’t upload an image so it looks even more confusing written out. I thought the root x would have moved up to become -2x^-1/2

But all I know is the answer is 49/8 and I have no clue how to get that!! I thought differentiation was easy so I’m stressing

I’m doing National 5 maths but from what I know,

For example if it says

F(x) = 3x + 7

Find the value of f(3)

You would then substitute the x for 3.

This means it would be

F(x)= 3(3) + 7

F(x)= 9 + 7

F(x)= 16

If however, it gives you an answer

For example if it says

F(x)=3x - 10

F(a)= -31. Find value of a

you would then do

3x - 10 = -31

(+10 to both sides)

3x = -21

(Divide by 3)

x= -7

Hope that helps, I have no clue how to do it if it’s not functions.

Original post by LSK104

I’m doing National 5 maths but from what I know,

For example if it says

F(x) = 3x + 7

Find the value of f(3)

You would then substitute the x for 3.

This means it would be

F(x)= 3(3) + 7

F(x)= 9 + 7

F(x)= 16

If however, it gives you an answer

For example if it says

F(x)=3x - 10

F(a)= -31. Find value of a

you would then do

3x - 10 = -31

(+10 to both sides)

3x = -21

(Divide by 3)

x= -7

Hope that helps, I have no clue how to do it if it’s not functions.

For example if it says

F(x) = 3x + 7

Find the value of f(3)

You would then substitute the x for 3.

This means it would be

F(x)= 3(3) + 7

F(x)= 9 + 7

F(x)= 16

If however, it gives you an answer

For example if it says

F(x)=3x - 10

F(a)= -31. Find value of a

you would then do

3x - 10 = -31

(+10 to both sides)

3x = -21

(Divide by 3)

x= -7

Hope that helps, I have no clue how to do it if it’s not functions.

sadly that is not the answer as it involves the derivate of the function

Original post by raggamuffin49

Can someone help me with this differentiation question?

Calculate f’(4) given that f(x) = (2x^2 - 2) / root x

Sorry I couldn’t upload an image so it looks even more confusing written out. I thought the root x would have moved up to become -2x^-1/2

But all I know is the answer is 49/8 and I have no clue how to get that!! I thought differentiation was easy so I’m stressing

Calculate f’(4) given that f(x) = (2x^2 - 2) / root x

Sorry I couldn’t upload an image so it looks even more confusing written out. I thought the root x would have moved up to become -2x^-1/2

But all I know is the answer is 49/8 and I have no clue how to get that!! I thought differentiation was easy so I’m stressing

Using index rules, when you divide by x^(1/2) you multiply (the whole numerator) by x^(-1/2), so use that to elminate the fraction and youre left with a relatively simple expression which can be differentiated as usual and then evaulate it when x=4.

(edited 2 months ago)

Original post by Blenxo

where is this question from is it from a higher paper?

https://www.highermathematics.co.uk/wp-content/uploads/2022/10/ESEP-3-Final.pdf

It probably would have been a better idea to post the link originally instead of describe the q 😂

Original post by RaggaMuffin49

Calculate f’(4) given that f(x) = (2x^2 - 2) / root x

Sorry I couldn’t upload an image so it looks even more confusing written out. I thought the root x would have moved up to become -2x^-1/2

But all I know is the answer is 49/8 and I have no clue how to get that!! I thought differentiation was easy so I’m stressing

Original post by RaggaMuffin49

Calculate f’(4) given that f(x) = (2x^2 - 2) / root x

Sorry I couldn’t upload an image so it looks even more confusing written out. I thought the root x would have moved up to become -2x^-1/2

But all I know is the answer is 49/8 and I have no clue how to get that!! I thought differentiation was easy so I’m stressing

Separate f(x) into two fractions. (2x^2)/root x -2/root x . Simplify the indices and then proceed as normal with the differentiation then sub in x = 4 after differentiating.

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