Heres the question:

Show that

I did this part since its simple algebra. .

Then the second part i'm stuck.

ii.) Hence write an expression in terms of n for

to n. Where it starts r = 1

Okey, so, method of differences.

I start by putting in r = 1

Then r = 2

Then r = n-1

Then r = n

Then r = r + 1

So then you add them all. Some cancel and im left with

Then i simplify and i get

And this is incorrect for the answer is

Thankyou for any help you can offer.

How do i do all these maths things to make it easier to read?

EDIT: Nvm i found the tutorial . I'll edit this with it now.