Brahmagupta's identity
In mathematics, Brahmagupta's identity says that the product of two numbers, each of which being a sum of two squares, is itself a sum of two squares. Specifically:
The identity holds in any commutative ring, but most usefully in the integers.
See also Euler's four-square identity. There is a similar eight-square identity derived from the Cayley numbers, but that isn't particularly interesting for integers because every positive integer is a sum of four squares.
Referenced By
Brahmagupta | Euler's four-square identity | List of mathematical topics | List of mathematical topics (A-C) | List of mathematics topics | List of number theory topics
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