a pair of perpen dicular straight lines passes through the origin and also through the point of intersection of the curve x*2 +y*2 =4 with x+y=a .the set containing the value of a is
a pair of perpen dicular straight lines passes through the origin and also through the point of intersection of the curve x*2 +y*2 =4 with x+y=a .the set containing the value of a is











