(adsbygoogle = window.adsbygoogle || []).push({}); Number theory--product of squares

1. The problem statement, all variables and given/known data

Suppose a and b are two integers, which can each be written as the sum of

two squares. Prove that ab can be expressed as the sum of two squares.

2. Relevant equations

3. The attempt at a solution

a=c[itex]^{2}[/itex]+d[itex]^{2}[/itex]

b=x[itex]^{2}[/itex]+y[itex]^{2}[/itex]

I'm not exactly sure how to approach this proof.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Number theory-product of squares

**Physics Forums | Science Articles, Homework Help, Discussion**