I'm stuck on this question:

State the principle of mathematical induction, and use it to prove that for

So far I've done this:

is a statement for each natural number , where . is true if:

- P(n) is true for n = 4.
- If it is true for arbitrary n, it is also true for n + 1.

For , , hence true.

For :

(Using hypothesis)

And that's where I get stuck. RHS should be , but that only occurs when n = 1.

Please help!