Question

What are the explicit equation and domain for an arithmetic sequence with a first term of 5 and a second term of 2?

Answer 1

@robtobey

Answer 2

notice the sequence 5, 2
how much was added/subtracted to "5" to get 2?

Answer 3

3?

Answer 4

hmm +3?

Answer 5

no -3

Answer 6

then THAT is the "common difference" or "d" in the equation for an arithmetic sequence, thus \(\bf a_{\color{brown}{ n}}=a_1+({\color{brown}{ n}}-1){\color{blue}{ d}}\implies a_{\color{brown}{ n}}=5+({\color{brown}{ n}}-1){\color{blue}{ (-3)}}\)

Answer 7

an = 5 − 3(n − 1); all integers where n ≥ 1

or an = 5 − 3(n − 1); all integers where n ≥ 0

Answer 8

well... the "n" a term.... and a term usually starts off at 1 onwards..... so \(\bf n \ge 1\)

Answer 9

thank you! can you help with some more? ill post them

Answer 10

yw sure, post away