If rs not equal to zero and the points (-r,s) and (s,-r) lie in same quadrant of the coordinate plane,is the point (a,b) in this same quadrant?
1. ab<0
2. sb>0
OA is A
1. ab<0
2. sb>0
OA is A
Create columns for all signs of r and stapanmittal wrote:If rs not equal to zero and the points (-r,s) and (s,-r) lie in same quadrant of the coordinate plane,is the point (a,b) in this same quadrant?
1. ab<0
2. sb>0
OA is A
If points are in the same quadrant, it means the points have the same sign for the x coodinate
In the table below, -r and s have the same signs, when r is negative and s is positive
r s -r -s
+ + - -
+ - - +
- - + +
- + + -
(-r,s) and (s,-r) are in the 1 quadrants, positive x and positive y
1. ab < 0
this means a is negative and b is positive or
this means b is negative and a is positive
Regardless of which, this point will not be in quad1 because its x and y points are not positive
sufficent
2. sb>0
We know s is positive, therefore b is positive
However we arent told anything about "a", therefore we cannot say if a is positive or negative
insufficient
ans = a
