A peaceful day for all,

a, b, c element N are known, where a, b, c build a pyth. trippel with a^2+b^2=c^2

tan (alpha)=a/b

is there a way to calculate tan (alpha/2) without using the angle ?

if not, how accurate i have to choose alpha to get a good result /

the rational number of tan (alpha/2) ?

Thanks in advance, if you give me a hint.

Greetings from the primes

Bernhard