Arithmetic Progressions - Sum Sn
Some exam boards expect you to be able to prove the formula for the sum Sn of the first n terms of an arithmetic sequence. In this video you are shown how.
" My whole class use your site "
Please help me to complete this project and keep it free for all to benefit from. More ...
Over 2000 videos have been completed so far and more go up most days, see my facebook page.