Skynt
Jun29-09, 10:33 PM
It should be really simple, but I think the algebra is bogging me down:
\frac{n!}{(n-i)! i!} + \frac{n!}{[n-(i+1)]! (i+1)!} = \frac{(n+1)!}{(n-i)! (i+1)!}
Can anyone show me the process of proving this? I don't see how the two expressions are equal...
essentially I can't get rid of the [n - (i + 1)]! term when I try to combine the two fractions and expand things.
\frac{n!}{(n-i)! i!} + \frac{n!}{[n-(i+1)]! (i+1)!} = \frac{(n+1)!}{(n-i)! (i+1)!}
Can anyone show me the process of proving this? I don't see how the two expressions are equal...
essentially I can't get rid of the [n - (i + 1)]! term when I try to combine the two fractions and expand things.