Let S = z ∈ C : z - 2 ≤ 1 , z 1 + i + z ¯ 1 - i ≤ 2 . Let z - 4   i attains…

Let S=zC:z-21,z1+i+z¯1-i2. Let z-4 i attains minimum and maximum values, respectively, at z1S and z2S. If 5z12+z22=α+β5, where α and β are integers, then the value of α+β is equal to ______.

Solution

Given z-21

x-22+y21     i represents interior region of a circle with centre 2,0 and radius 1

Now z1+i+z¯1-i2

Puting z=x+iy, we get

x+iy1+i+x-iy1-i2

x-y+ix+y+x-y-ix+y2

 x-y1    i

Let A1,0 and B2,1 be the points on the line x-y=1 and the circle x-22+y2=1

z-4i represents the distance from P0,4 to any point in the region S

Here PA=17, PB=13 

So A1,0 is the point representing z2

Let D2+cosθ,0+sinθ be the point representing z1

 mCP=tanθ=-2

cosθ=-15,sinθ=25

  D2-15,25

z1=2-15+2i5

So z1=25-455 & z2=1

 z22=1

 5z12+z22=30-45

α=30

β=-4

Hence α+β=26

Asked in: JEE Main 2022 (29 Jun Shift 1)

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