5 • Tip for calculating square root of complex no in mind

Mental Calculation, Mathematics, and Puzzles
7

Sorry, I didn’t see your post until now. I get a lot of notifications, and sometimes I miss them.

The edits mainly just added dollar signs around the formulas so that MathJax would format them.

Before:

Square root of 7 - 24i
|z| = √7^2 +24^2 = √49+ 576 = √625 = 25

     √25+7÷2 - i√25- 7÷2
       =     √16 - i√9
       =  (4 - 3i ) is the square root.

After:

Square root of 7 - 24i
|z| = √(7^2 + 24^2) = √(49+ 576) = √625 = 25

√\frac{25+7}{2} - i√\frac{25-7}{2}
= √16 - i√9
= 4 - 3i is the square root.

More info:

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