OG 11 - Coordinate Geometry

albertrahul · Posted: Wed Jul 09, 2008 6:32 am Post subject: OG 11 - Coordinate Geometry

In the rectangular coordinate system, are the points (r,s) and (u,v) equidistant from the origin?

(1) r + s = 1
(2) u = 1 - r and v = 1 - s

Please explain your solution. Thanks!

augusto · Posted: Wed Jul 09, 2008 7:34 am Post subject:

I might be tired after working all day, but I think it's E.

Because if you put both statements together you end up with 3 equations and 4 variables.

Cheers,

olika · Posted: Wed Jul 09, 2008 7:55 am Post subject: Re: OG 11 - Coordinate Geometry

The answer is C, right?

I solved it just by picking numbers. Not very safe method, i know...

Very Happy

olika · Posted: Wed Jul 09, 2008 8:06 am Post subject: Re: OG 11 - Coordinate Geometry

I think you can solve it like this.

We know that r+s=1, so we can conclude that r=1-s and s=1-r.

Then we have u=1-r and v=1-s. We can substitute like this u=1-(1-s), which means u=s. The same way, v=r. Thus, we can conclude that two points equidistant from (0,0)

aj5105 · Posted: Sat Oct 04, 2008 7:56 am Post subject:

imo -- taking numbers and solving is quick and hassle free..

kris610 · Posted: Sat Oct 04, 2008 8:43 am Post subject:

I think it would be C.

A and B together tell you that r=v, u=s => The two points are (v,s) (s,v).

Both the points are at a distance of sqrt(v^2+s^2) from the origin.