Explore Westonci.ca, the premier Q&A site that helps you find precise answers to your questions, no matter the topic. Get quick and reliable solutions to your questions from a community of experienced experts on our platform. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

Use the arithmetic sequence of numbers 1, 3, 5, 7, 9,.to find the following:

a) What is d, the difference between any two consecutive terms?
b) Using the formula for the nth term of an arithmetic sequence, what is 101st term?
c) Using the formula for the sum of an arithmetic sequence, what is the sum of the first 20 terms?


Sagot :

luana
[tex]a)\\\\ a_{n+1}-a_n=d\\ for\ n=1\\ a_2-a_1=d\\ d=3-1=2\ - difference\ between\ two\ consecutive\ terms\\\\ b)\\ a_n=a_1+(n-1)d\\ n=101\\ a_{101}=1+(101-1)*2\\ a_{101}=1+100*2=200+1=201\\\\ c)\\ Sn=\frac{a_1+a_n}{2}*n\\ n=20\\ a_n=a_{20}=1+(20-1)*2=1+38=39\\ Sn=\frac{1+39}{2}*20=400\ \ Sum\ of\ the\ first\ 20 \ numbers.[/tex]