The condition ∣z+4∣≤3 describes a disc centred at −4 with radius 3. Writing z+1=(z+4)−3 and using the triangle inequality, ∣z+1∣≤∣z+4∣+3≤3+3=6. The greatest value 6 is attained at the boundary point farthest from −1, namely z=−7.
JEE Main · 2007 · 29 Apr 2007 · Offline · Single correct option