So what is LOCUS????????

[supermike]

hi everyone i just been through conics and the only trouble i had with this topic is the locus problem. the details like the pt a chord goes through and midpt of a chord reveal no clue to me watsoever. i seen heaps of worked solutions of conics locus questions and failed to find any connection or a pattern of solving it. so now i post this thread to hopefully get enlightened. what is the primary objective of every locus question??? i would love to be let in a general idea, a collective thought on how a locus problem in relation to conics is usually solved. thanks heaps guys!!!!!!!

 

[L]

 

[twilight1412]

is this really extension 2?

^ nice photo btw

the short and dumbed down version is .. its basically a formula which fufills certain requirements as stated by the question =/

 

[vds700]

Formally, a locus is defined as a point which obeys a given condition. Its position can vary in the plane as long as that condition is satisfied.


In conics, you will usually be asked to find the locus of a variable point whose coordinates are given in terms of a parameter say t or theta.

eg M(t, 1/t)
x=t....(1)
y=1/t.....(2)

sub 1 into 2 to get xy =1, so the locus of M is a rectangular hyperbola.

Basically the idea is to eliminate the parameter to find the cartesian equation of the locus

 

[maths-bbqz]

A locus question always gives you the x- & y- parametric coordinates and another equation with the parameter.
If it's not like that, then the parameter is easily eliminated, or it's just that you havent picked up on the equation involving the parameter OR theres another algebraic trick involved which is trickier and is individual to the question.

So i guess with your question if you really need help actually post it so people can help

 

[MaNiElla]

locus

 

[youngminii]

"Find the locus of blahblahblah certain conditions blahblahblah"
=
"Find the equation of blahblahblah certain conditions blahblahblah"

 

[PattieBoi]

Locus?

Isn't that a bug or some shit?

 

[cutemouse]

Locus?

Isn't that a bug or some shit?

A locust is an insect

 

[kaz1]

You just eliminate t. It's a bit harder than the Extension 1 locus questions.