How do I find the sum of the arithmetic sequence 3, 5, 7, 9, ..., 21?
2 Answers
Jul 11, 2018
Explanation:
Given arithmetic sequence
The first term
If there are
hence the sum of given arithmetic progression (
Jul 11, 2018
Explanation:
#"the sum to n terms of an arithmetic sequence is"#
#•color(white)(x)S_n=n/2[2a+(n-1)d]#
#"where a is the first term and d the common difference"#
#"here "a=3,d=7-5=5-3=2,n=10#
#S_(10)=5[(2xx3)+(2xx9)]#
#color(white)(xx)=5(6+18)=120#