Math Is Fun Forum

mukesh

Member

Registered: 2010-07-18

Posts: 31

locus in co-ordinate geometry

sir plse reply quickly ,i m in very trouble.
'A POINT(6,-8) IS IN XY PLANE.FIND THE LOCUS OF THE MID POINT OF ALL THE POSSIBLE LINES DRAWN FROM THIS POINT WHICH INTERSECT X-AXIS.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: locus in co-ordinate geometry

Hi;

I am getting y = - 4.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,626

Re: locus in co-ordinate geometry

hi mukesh,

Did you try plotting a few points to see what happens?

Let the 'other' end of the line be at (x,0)

The end points are (x,0) and (6,-8)

So what is the y coordinate of the midpoint?

That should fix the locus for you. 

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

{7/3}

Member

Registered: 2013-02-11

Posts: 210

Re: locus in co-ordinate geometry

Not sure,but won't the locus be a segment of a parabola?

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There are 10 kinds of people in the world,people who understand binary and people who don't.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: locus in co-ordinate geometry

Hi;

I assumed he meant all the line segments from (6,-8) to the x axis. A few sample points are shown with the red point being the midpoint.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

{7/3}

Member

Registered: 2013-02-11

Posts: 210

Re: locus in co-ordinate geometry

Sorry,i mixed up locus and envelope.

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There are 10 kinds of people in the world,people who understand binary and people who don't.