#### You may also like

Find all real solutions of the equation (x^2-7x+11)^(x^2-11x+30) = 1.

### Telescoping Series

Find $S_r = 1^r + 2^r + 3^r + ... + n^r$ where r is any fixed positive integer in terms of $S_1, S_2, ... S_{r-1}$.

### Growing

Which is larger: (a) 1.000001^{1000000} or 2? (b) 100^{300} or 300! (i.e.factorial 300)

# Tens

##### Age 16 to 18 Challenge Level:
You could write $9^n$ as $(10-1)^n$ and consider the terms of the binomial expansion...

Or you could use Modular Arithmetic - there's a useful introduction here.