1.Look at the right-hand-sides of your three equationsOriginally Posted by Natasha
2. Do you notice anything about the fractions which occur
just before the first n in each of these?
3. Look at the part on the right-hand-side after the fraction,
is there something you can do to one of these to get the next?
4. Do the things you have noticed generalise?
5. Can these sums be rearranged to give any other sums which
might be of interest?