why do we substitute t values back into P(at^2,2at)
3E question 4b
- Thread Starter
- 26-04-2016 08:53
- 26-04-2016 09:08
I don't understand your question. However, this may help.
If we take a curve which is double valued in y such as a circle the the formula is which is not a function as it is double valued, i.e each value of x does not lead to only one value of y
Introducing a parameter to give us gives us two single valued functions and by using values of t 0<t<=360 we can plot the function.
The same is the case for a parabola which we swap a sqrt form (not a function) for the parameterised version of (say) x=at^2, y=at
This enables us to find proper functions in t for the gradient etc using the chain rule.
Does that answer in any way what you are asking?Last edited by nerak99; 26-04-2016 at 09:10.
- 26-04-2016 09:13
Soory, forgot to address the specific question. By eliminating t we end up with a cartesian form with y^2 in it. which we root out to find the form y=f(x) (the cartesian form) which is not as useful in a mathematical sense but at least has the benefit of getting us a mark or two at FP1
- 26-04-2016 09:34