Parametrics (1 Viewer)

[Xayma]

You need to be able to justify it at the beginning, ie say let a=1/4 or ect. Let p=2 etc.

 

[Estel]

But then... what if a doesn't = 1/4.... on what premise can you say a = 1/4?

 

[Li0n]

:/
"Sketch the parabola whose parametric equations are x = t and y = t^2 bla bla bla"
x^2 = y
is in the form of x^2 = 4ay
:. a = 1/4
.

 

[Estel]

That's fine. I thought you meant assuming things which weren't given, as implied by this...

or do you have to work with the proper values at the start.

 

[frazzle]

we've finished the maths ext course, and i have never seen the two point formula before!

(y-y1)/(x-x1)=(y2-y1)/(x2-x1)

can someone please reassure me we don't need to know it!?

 

[mishka]

sorry to shatter your dreams, but you REALLY need to know it... if you did advanced maths in year 10 you should have covered it anyway....

but then again if you've learnt y-y1=m(x-x1) it's virtually the same because m=y2-y1/x2-x1

 

[mojako]

but then again if you've learnt y-y1=m(x-x1) it's virtually the same because m=y2-y1/x2-x1

so, then conclusion is, you dont need to learn it

 

[frazzle]

phew, thanks!

parametrics are ugly enough as it is, when i know how to do a question, i get bogged down in those ugly "a"s, "p"s and "q"s and end up with a big old mess =(

lets hope they don't ask many parametrics Qs worth many marks!