A Pythagorean triple is a group of three whole numbers (integers) that satisfies the equation a2 + b2 = c2, where c is the measure of the hypotenuse.
Let a = i2 - j2, b = 2ij, and c = i2 + j2 where i and j are integers.
Then, a2 + b2 = (i2 - j2)2 + (2ij)2 = i4 - 2i2j2 + j4 + 4i2j2 = i4 + 2i2j2 + j4 = (i2 + j2)2 = c2