To simplify (√3 + 2√5)², first apply the FOIL method, resulting in (√3)² + 2(√3)(2√5) + (2√5)². This expands to 3 + 4√15 + 20. Combining the constant terms gives a final result of 23 + 4√15. The step-by-step approach effectively demonstrates the simplification process.
I just saw this one. If there are finitely many primes, then
##0<\prod_{p}\sin(\frac\pi p)=\prod_p\sin\left(\frac{\pi(1+2\prod_q q)}p\right)=0##
Of course it is in a way just a variation of Euclid's idea, but it is a one liner.