let r1, r2, x0, x1, x2 be Real; for f1, f2 being Function of REAL,REAL holds [!((r1 (#) f1) + (r2 (#) f2)),x0,x1,x2!] = (r1 * [!f1,x0,x1,x2!]) + (r2 * [!f2,x0,x1,x2!])
let f1, f2 be Function of REAL,REAL; [!((r1 (#) f1) + (r2 (#) f2)),x0,x1,x2!] = (r1 * [!f1,x0,x1,x2!]) + (r2 * [!f2,x0,x1,x2!])
[!((r1 (#) f1) + (r2 (#) f2)),x0,x1,x2!] =
[!(r1 (#) f1),x0,x1,x2!] + [!(r2 (#) f2),x0,x1,x2!]
by Th6
.=
(r1 * [!f1,x0,x1,x2!]) + [!(r2 (#) f2),x0,x1,x2!]
by Th5
;
hence
[!((r1 (#) f1) + (r2 (#) f2)),x0,x1,x2!] = (r1 * [!f1,x0,x1,x2!]) + (r2 * [!f2,x0,x1,x2!])
by Th5; verum