Hi!

Can anyone help me solcing these excercises please?

a. Prove that 1*2+2*3+...+n(n+1)=[n(n+1)(n+2)]/3

b. 1*2*3+2*3*4+...+n(n+1)(n+2)=?

Cheers

Printable View

- Oct 11th 2011, 11:47 AMKelvin88Two induction exercise
Hi!

Can anyone help me solcing these excercises please?

a. Prove that 1*2+2*3+...+n(n+1)=[n(n+1)(n+2)]/3

b. 1*2*3+2*3*4+...+n(n+1)(n+2)=?

Cheers - Oct 11th 2011, 11:55 AMPlatoRe: Two induction exercise
- Oct 11th 2011, 11:58 AMemakarovRe: Two induction exercise
There is a plan to follow for each proof by induction, and you don't have to think much to advance quite a bit. If you don't have anything better, you can find one description here. Or explain what exactly you don't understand. See also rule #11 in this sticky thread.

- Oct 11th 2011, 12:12 PMKelvin88Re: Two induction exercise
Ok, i understand. I am sorry, actually these are from my homework (the easier ones), but have no idea how to start. Maybe at a. I should prove for P(1), then for P(n+1)? Then it will be 1*2+2*3+...+(n+1)(n+2) ?

For b. I have no idea what should I do:( - Oct 11th 2011, 12:27 PMemakarovRe: Two induction exercise