How do you write a rule for the nth term of the arithmetic sequence and then find a_22a22 given d=14, a_6=-10d=14,a6=10?

1 Answer
Sep 9, 2017

a_n= a_1+(n-1)d , a_22=214an=a1+(n1)d,a22=214

Explanation:

For arithmatic progression series ,

nn th term is a_n= a_1+(n-1)d an=a1+(n1)d, where a_1.n,da1.n,d are

first term , number of terms and common difference respectively.

a_6=-10 , d=14 , n=6 , a_1= ? :. -10 = a_1+(6-1)*14

or a_1= -10-70= -80 ; a_22=?

a_22= a_1+(n-1)d or a_22= -80 +(22-1)*14 or

a_22= -80 +294 =214 [Ans]