All Junior Cert Mathematics posts
• #### Sequences and Patterns sarah_nunan

Does anyone know how to find the nth term of sequences?

1. #### SryanBruen

Halve the second difference to get the number of n2s for example if you the second difference of a sequence is +6 (which would be constant) you would divide 6 by 2 to get 3 therefore this becomes 3n2

In fact the following rules apply when determining the number of n2s

Write out the original sequence above the terms of your number of n2

Subtract the n2s from the sequence to give the Residue

The residue will either be constant or a linear sequence. If it is a linear sequence then work out its formula.

Finally add the number of n2s to the formula for the residue and this will be the formula for the original sequence.

2. #### SryanBruen

The 2s are squared by the way (so like n2 = n squared). This only goes for quadratic sequences ^!

3. #### sarah_nunan

Thank you so much! I have a test on them tommorrow😅

4. #### StudyIsMyLief

nice one these notes r good, not like toys r us