For the sequence 8,11,14,17 1) find nth term. 2)the 20th term?

1 Answer
Jim G.
Oct 29, 2017

#a_n=3n+5,a_20=65#

Explanation:

#"the given terms form the terms of an "color(blue)"arithmetic sequence"#

#a,a+d,a+2d,a+3d,......, a+(n-1)d#

#"where a is the first term and d the "color(blue)"common difference"#

#d=a_2-a_1=a_3-a_2=......=a_n-a_(n-1)#

#"here "d=11-8=14-11=17-14=3#

#"the nth term is "#

#•color(white)(x)a_n=a+(n-1)d#

#rArra_n=8+3(n-1)=8+3n-3#

#rArra_n=3n+5larrcolor(blue)"nth term formula"#

#rArra_(20)=(3xx20)+5=65#

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