Let a2=m & b2=N then m > 0 and N > 0 Now given condition is M+N>1andM2+N2<1

(M,N) lies inside circle x2+y2<1 and above line x + y > 1 ⇒ (M, N) lies in shaded region and number of points in shaded region are infinite, so number of pair (a,b) are also infinite.