Billion's maths methods (units 1 + 2) question thread.

[Billion]

Disclaimer: You may lose brain cells as a result of reading some of the questions posted here.
Here is where I'll post my maths methods questions relating to units 1 + 2.

I'm pretty shit at maths, so if you're explaining a difficult concept make sure you explain as you would to a monkey.

[Billion]

Relating to the position-time graph x(t)=4t-t^2
Find the gradient at t=2

[pi]

Relating to the position-time graph x(t)=4t-t^2
Find the gradient at t=2

Hint: Do you know differentiation or the concept of gradient at turning points?

[DetteAmelie]

Relating to the position-time graph x(t)=4t-t^2
Find the gradient at t=2

If you're looking for the gradient at t=2
1) You need to derive the function

Spoiler

Dx/dt = -2t+4

2) Let t=2

Spoiler

dx/dt = -2(2) + 4
=-4 +4
=0

Spoiler

Therefore, the gradient at t=2 is 0

[Billion]

Pi: I haven't been taught the dy/dx method. (I'm working a little a head :s)

Colibri: Ooo, okay that makes sense. I should read up on that, it's a couple of chapters ahead I think.

[pi]

Pi: I haven't been taught the Dx/dy method. (I'm working a little a head :s)

Turning points have a gradient of 0. That equation has a turning point at t=2 (either solve by putting into turning point form, or using symmetry from the x-ints, or sketching it, or t=-b/2a, or any number of methods).

You don't need any calculus to get this answer

[DetteAmelie]

Pi: I haven't been taught the dy/dx method. (I'm working a little a head :s)

Colibri: Ooo, okay that makes sense. I should read up on that, it's a couple of chapters ahead I think.

Actually, listen to Pi. You don't need to read ahead about if you haven't been taught it yet.  What Pi says is equally as valid and is definitely much more useful in terms of this question.

[Billion]

Thank you both! Appreciated.