theorem :: DIFF_3:38

for x0, x1, x2, x3 being Real
for f being Function of REAL,REAL st ( for x being Real holds f . x = sqrt x ) & x0,x1,x2,x3 are_mutually_distinct & x0 > 0 & x1 > 0 & x2 > 0 & x3 > 0 holds
[!f,x0,x1,x2,x3!] = ((((sqrt x0) + (sqrt x1)) + (sqrt x2)) + (sqrt x3)) / (((((((sqrt x0) + (sqrt x1)) * ((sqrt x0) + (sqrt x2))) * ((sqrt x0) + (sqrt x3))) * ((sqrt x1) + (sqrt x2))) * ((sqrt x1) + (sqrt x3))) * ((sqrt x2) + (sqrt x3)))