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avatar+73 

Let z be a complex number such that |z|=1.

Find the maximum value of |1+z|+|1-z+z2|.

 Jul 24, 2025
 #1
avatar+214 
-1

The maximum value is 45/4.

 Jul 25, 2025
 #4
avatar+73 
+1

The solution was actually 13/4.

Clnsbstnkng  Jul 25, 2025
 #2
avatar+67 
+1

|z|=1

z=1 or -1

if z=1,

|1+1|+|1-1+1^2|=2+1=3

if z=-1,

|1-1|+|1+1+(-1)^2|=0+3=3

it can only be 3

proof:

|z|=1

z^2=1

|1±z|+|1±z+1|=1±z+1±z+1=3±z±z, one has the be -1 so 3

 

 
 Jul 25, 2025
edited by bqimath  Jul 25, 2025
 #3
avatar+73 
+1

The solution was actually 13/4.

Clnsbstnkng  Jul 25, 2025

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