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matt.lmx
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Homework Statement
Where z is a complex number:
|4+z| - |4-z| = 6
Prove that |4+z|^2 - |4-z|^2 >= 48
2. The attempt at a solution
|4+z| = 6 + |4-z|
|4+z|^2 = 36 + |4-z|^2 + 12|4-z|
|4+z|^2 - |4-z|^2 = 36 + 12|4-z|
From here, I figure if I can prove that |4-z| >= 1, I can prove that |4+z|^2 - |4-z|^2 >=48
Any pointers as to how I can do this? Or am I approaching this from the wrong angle?