### Telescoping Series

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

### Degree Ceremony

What does Pythagoras' Theorem tell you about these angles: 90Â°, (45+x)Â° and (45-x)Â° in a triangle?

### OK! Now Prove It

Make a conjecture about the sum of the squares of the odd positive integers. Can you prove it?

# Seriesly

##### Age 16 to 18Challenge Level

Possible support
Try the problems Natural Sum, More Sequences and Series, and OK Now Prove It
Read the article Proof by Induction.

Possible extension
Telescoping Series