Complex Number Kookiness 7

Observe the table below. Can you find something interesting in any 1 of the 2 columns?

Brain saying "WOW!"
Complex Numbers Absolute Values of Complex Numbers Squared
½+i
½+2i
½+3i
½+4i 16¼
½+5i 25¼
½+6i 36¼
½+7i 49¼
½+8i 64¼

The fraction ½ is added to consecutive integers multiplied by the imaginary unit i in the left column so that the squares of the absolute values of the complex numbers are equal to the squares of the consecutive integers + ¼! If the real & imaginary parts of the complex numbers swapped values, then their absolute values would stay exactly the same! The signs of the real part & imaginary part of each complex number doesn't matter because that won't change the absolute value!

Complex Numbers Absolute Values of Complex Numbers Squared
1+½i
2+½i
3+½i
4+½i 16¼
5+½i 25¼
6+½i 36¼
7+½i 49¼
8+½i 64¼

Below is a copy of the 1st table, except that this time, I printed the conjugates of the complex numbers!

Complex Numbers Absolute Values of Complex Numbers Squared
½-i
½-2i
½-3i
½-4i 16¼
½-5i 25¼
½-6i 36¼
½-7i 49¼
½-8i 64¼

The main difference between a complex number & its conjugate is that the plus sign in the middle becomes a minus; or if it's already a minus, it becomes a plus!

Here are the conjugates of the ones for the 2nd table:

Complex Numbers Absolute Values of Complex Numbers Squared
1-½i
2-½i
3-½i
4-½i 16¼
5-½i 25¼
6-½i 36¼
7-½i 49¼
8-½i 64¼

By the way, |a+bi| = |a-bi| = |-a+bi| = |-a-bi|; all 4 of those are exactly the same!(In absolute value) You can have the variables a & b swap places without changing the absolute value!

The absolute value of a complex number:

The absolute value of a + bi = the square root of the sum of a^2 and b^2

Finally, here's the appropriate formula for this math trick:

|½ ± Ni|2 = |N ± ½i|2 = N2 + ¼

Back to Index Page Back to Math Trick Menu

© Derek Cumberbatch