Q12 Q12. The value of 'c' for which the set, {(x , y) | x2 + y2 + 2x ≤ 1} ⌒ { (x, y) [ x – y + c ≥ 0} contains only one point in common is : (a) - ∞ , - 1 ⌒ [ 3, ∞ ) (b) { – 1, 3} (c) { – 3} (d) { – 1} Share with your friends Share 0 Shruti Tyagi answered this Dear student, First set is the set of points inside a circle with centre at (-1,0) and radius as 12--1=2And the second set is that of the right side of a line, (the side of which can be found by taking an example of this family x-y=0. If we go towards positive x axis, the condition gets satisfied).For only one point to be common, the line must be a tangent to the circle or perpendicular distance of line x-y+c=0 from centre of circle (-1,0) is 2so,|−1–0+c|12+-12=2 |c-1|2=2c-1=2Either c-1=2 or - c-1=2⇒c=3 or -c+1=2⇒c=-1The condition x-y+3≥0 is satisfied by centre and that means the circle is on the right side of line x-y+3=0.so the answer is c=-1thus option d is correct Regards 0 View Full Answer Lithin K Ninan answered this a) 0