In the xy plane, are the points (r,s) and (u,v) equidistance from the origin ?
1. r+s=1
2. u=1-r and v=1-s
1. r+s=1
2. u=1-r and v=1-s
Distance of (r,s) from origin = r^2 + s^2akpareek wrote:In the xy plane, are the points (r,s) and (u,v) equidistance from the origin ?
1. r+s=1
2. u=1-r and v=1-s
Question is asking IS r^2+s^2 = U^2 + v^2
or u^2 - r^2 = s^2-v^2
St1 doesnt give info about (u,v). INSUFF
St2:
u=1-r and v=1-s
u^2 = 1+r^2 -2r
u^2-r^2 = 1-2r
Similarly, v^2 -s^2 = 1-2s
No info available yet. because we do not know about r and s values.
INSUFF
Combining:
u^2-r^2 = 1-2r
v^2 -s^2 = 1-2s
Add these two
u^2+v^2-(r^2+s^2) = 2-2(r+s)
u^2+v^2-(r^2+s^2) = 2-2(1)
u^2+v^2-(r^2+s^2) = 0
Hence
u^2+v^2=(r^2+s^2)
SUFF
pick C
r+s =1
