The Student Room Group
Reply 1
what about gradient function. need more detail.

i did one on gradient function where i had to use differentiation. If its the same one i can help.
Reply 2
confused?
what about gradient function. need more detail.

i did one on gradient function where i had to use differentiation. If its the same one i can help.


Er, well my teacher hasn't mentioned anything about differentiation. But anyway, we have to investigate the gradient function for the set of graphs y=ax with a little n as the integer.
Reply 3
You can approximate the gradient by drawing a tangent.

But you will get a more accurate answer if you use a calculator in the following way.

Say you want to know the gradient of the curve y = x^5 (ie, y = x raised to the power 5) when x = 3.

That gradient is approximately

[(3 + very small number)^5 - 3^5] / (very small number)

The "very small number" has to be the same in both places.

For example, you could calculate

(3.00001^5 - 3^5)/(0.00001) = 405.003
Reply 4
Jonny W
You can approximate the gradient by drawing a tangent.

But you will get a more accurate answer if you use a calculator in the following way.

Say you want to know the gradient of the curve y = x^5 (ie, y = x raised to the power 5) when x = 3.

That gradient is approximately

[(3 + very small number)^5 - 3^5] / (very small number)

The "very small number" has to be the same in both places.

For example, you could calculate

(3.00001^5 - 3^5)/(0.00001) = 405.003


Thanks for that! At the moment I am drawing the graphs for y=x², y=x³, y=2x², y=x³, etc and then finding the gradient from them by drawing a tangent to the curve. What I don't understand is how to find the pattern, which is what we are supposed to do now.
Reply 5
Melanie47
Thanks for that! At the moment I am drawing the graphs for y=x2, y=x3, y=2x2, y=x3, etc and then finding the gradient from them by drawing a tangent to the curve. What I don't understand is how to find the pattern, which is what we are supposed to do now.


The pattern for y = x^2 is easy to spot - if you're good at drawing tangents (or use the calculator method).

x | gradient of curve at x
-------------------------
0 | 0
1 | 2
2 | 4
3 | 6
4 | 8
5 | 10
Reply 6
Jonny W
The pattern for y = x^2 is easy to spot - if you're good at drawing tangents (or use the calculator method).

x | gradient of curve at x
-------------------------
0 | 0
1 | 2
2 | 4
3 | 6
4 | 8
5 | 10


Heh... I feel like a real fool now. I'm not very good at drawing tangents :redface:

ETA: Hope you don't mind if I decide to pm you later if I need some more help :smile:
Reply 7
I really need help with this coursework :frown: If anybody could pm me with any help that would be great!
Reply 8
Please! I really need help with this!
Reply 9
Have you found the pattern for y = x^3 ?
Reply 10
Jonny W
Have you found the pattern for y = x^3 ?


I've found the patterns... it's just the formulae I'm having trouble coming up with.
Reply 11
What pattern have you found for y = x^3 ?