The Student Room Group

parametric equation x=3t^2 and y=2t^3

I do not understand what i have to do, i need to make y the subject but this is confusing.
The question is parametric equation x=3t2 and y=2t3
find the cartesian equation for the curve with these parametric equations.
Reply 1
Avatar for Meg94
Meg94
How about trying to rearrange the x equation to make t the subject, and then substitute that into your y equation? :smile:
Reply 2
Avatar for HEY_101
HEY_101
OP
2
Tried that but it does not look right, and I'm confused on how to simplify it
Reply 3
Avatar for Atheism
Atheism
8
Original post by HEY_101
Tried that but it does not look right, and I'm confused on how to simplify it


How about you show us what you've got, and we'll say where/if you've gone wrong.
Reply 4
Avatar for HEY_101
HEY_101
OP
2
t= x/3\sqrt{x/3}
then i put it into y
so 2(x/3\sqrt{x/3})3
then im confused
(edited 11 years ago)
Reply 5
Avatar for a10
a10
19
Original post by HEY_101
t= x/3\sqrt{x/3}
then i put it into y
so 2(x/3\sqrt{x/3})3
then im confused


ill give you a clue

whats root x cubed? and whats 3 cubed? try that :smile:
Reply 6
Avatar for HEY_101
HEY_101
OP
2
2(x2/3/32/3)
Reply 7
Avatar for a10
a10
19
Original post by HEY_101
2(x2/3/32/3)


root x cubed is root x and 3 cubed is 27 so u have root x/ 27 in brackets and multiply by 2 and clean up the fraction.
Reply 8
Avatar for ezioaudi77
ezioaudi77
Original post by Benjy100
OH HOW EMBARRASSING! THE SHAME, THE SHAME I SAY!

No but in all seriousness it looks neater in the form I wrote it in, as opposed to resorting to a plus-minus sign...


Sorry my mistake, I thought I read the question as "find a Cartesian equation in the form y=f(x)", so can actually keep it in that form :smile:
Reply 9
Avatar for a10
a10
19
Original post by Benjy100
OH HOW EMBARRASSING! THE SHAME, THE SHAME I SAY!

No but in all seriousness it looks neater in the form I wrote it in, as opposed to resorting to a plus-minus sign...

EDIT - Yes you walk away old chap, this duel has been won by me - you fought bravely, but only one could be victorious


you dont have to write it as y= something it depends on the question but yes benji posted the right solution :smile: however in future please let the OP figure it out first :wink:
Reply 10
Avatar for ezioaudi77
ezioaudi77
Original post by Benjy100
Ah then we shall shake hands cordially and our paths shall diverge - who knows when we shall meet again? ONLY TIME WILL TELL


what have you been smoking?
Reply 11
Avatar for HEY_101
HEY_101
OP
2
Thanks everyone for helping me see where i was going wrong :biggrin:
Reply 12
Avatar for a10
a10
19
Original post by ezioaudi77
what have you been smoking?


hahahaha this is exactly what i was thinking :ahee:

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you