This final post on this topic will look at geometrical sequences. Again you need to know how to use the formulae in the formula book. One difference to arithmetic sequences is that you also have an infinite sum formula. This can be used when the common ratio r is between but not includingÂ -1 and 1.

Geometric questions can be combined with logs so come back to this topic again when you’ve had time to look at logs. As always if you need more help then just ask at our Facebook Support Group (link on the right)

June 2007 Question 2 – answer here

June 2010 Question 5 – answer here

If you are stuck then try this video for help