calculate the sum of the first 50 terms. 1+9+17+ ...
Follow Math Help Forum on Facebook and Google+
Use $\displaystyle S_n = \frac{n}{2}(2a+(n-1)d)$ n=50 so, $\displaystyle S_{50} = \frac{50}{2}(2a+(50-1)d)$ now all you need is 'a' the first term and 'd' the common difference from the series, what do you get?
thanks. and whats the geometric series forumla???
Read this fella Geometric series - Wikipedia, the free encyclopedia
what does the r represent?
Originally Posted by ahmedb what does the r represent? r is defined in the article linked by pickslides ... look for it.
View Tag Cloud