If for the complex numbers   z satisfying | z - 2 - 2 i | ≤ 1 , the maximum value of | 3 i z + 6…

If for the complex numbers z satisfying |z-2-2i|1, the maximum value of |3iz+6| is attained at a+ib, then a+b is equal to _____ .

Solution

Given that: |z-2-2i|1 which represents a circle with centre at (2,2) and radius =1.

Now |3iz+6|=|3i(z-2i)|=|3i||z-2i|

As we know that,  |z1z2|=|z1||z2|

From tha diagram we can see that, |3iz+6|=3|z-2i| is maximum at z=3+2i because a point on the circle, which has maximum distance from (0,2) is (3,2).

So, a=3 & b=2

a+b=5

Asked in: JEE Main 2021 (01 Sep Shift 2)

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