theorem :: DIFF_3:37

for x0, x1, x2 being Real
for f being Function of REAL,REAL st ( for x being Real holds f . x = sqrt x ) & x0,x1,x2 are_mutually_distinct & x0 > 0 & x1 > 0 & x2 > 0 holds
[!f,x0,x1,x2!] = - (1 / ((((sqrt x0) + (sqrt x1)) * ((sqrt x0) + (sqrt x2))) * ((sqrt x1) + (sqrt x2))))