let n be Nat; for a being non negative Real holds Product ((a,1) Subnomial n) = a |^ ((n + 1) choose 2)
let a be non negative Real; Product ((a,1) Subnomial n) = a |^ ((n + 1) choose 2)
set l = a |^ (n choose 2);
set f = (a,1) Subnomial n;
set g = (1,a) Subnomial n;
A1: ((n + 1) choose 2) * 2 =
((n * (n + 1)) / 2) * 2
by NUMPOLY1:72
.=
n * (n + 1)
;
A2: (a |^ ((n + 1) choose 2)) |^ 2 =
a |^ (((n + 1) choose 2) * 2)
by NEWTON:9
.=
Product (((a * 1),(a * 1)) Subnomial n)
by A1, PRA
.=
Product (((a,1) Subnomial n) (#) ((1,a) Subnomial n))
by ST
.=
(Product ((a,1) Subnomial n)) * (Product ((1,a) Subnomial n))
by PRN
.=
(Product ((a,1) Subnomial n)) * (Product ((a,1) Subnomial n))
by SFE, RVSUM_3:4
.=
(Product ((a,1) Subnomial n)) |^ 2
by NEWTON:81
;
a |^ ((n + 1) choose 2) =
sqrt ((Product ((a,1) Subnomial n)) |^ 2)
by A2
.=
Product ((a,1) Subnomial n)
;
hence
Product ((a,1) Subnomial n) = a |^ ((n + 1) choose 2)
; verum