JEE Main 2021 (Online) 1st September Evening ShiftQuestion 1
If for the complex numbers $z$ satisfying $|z-2-2i|\le1$, the maximum value of $|3iz+6|$ is attained at $a+ib$, then $a+b$ is equal to ______.
Complex Numbers
Answer$5$
Solution
$|3iz+6|=3|z-2i|$. On the disc centred $2+2i$ (radius $1$), the farthest point from $2i$ is $2+2i+1=3+2i$, so $a+b=5$.