



 
Hi Rita, Let me try a different example
The letter n tells you the term number so n = 1 gives the first term, n = 2 gives the second term, n = 3 gives the third term and so on. thus
Thus the first 4 terms are 3/5^{2}, 3^{2}/5^{3}, 3^{3}/5^{4} and 3^{4}/5^{5} You might expand the terms and write them 3/25, 9/125/, 27/625 and 81/3125 but I find the first form more useful. In particular when I look at 3/5^{2}, 3^{2}/5^{3}, 3^{3}/5^{4} and 3^{4}/5^{5} I see that each term is 3/5 times the previious term and hence the common ratio is 3/5. I hope this helps,  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 