Question

Here are the first five terms of an arithmetic sequence.

26 19 12 5 –2

Find an expression, in terms of n for the n term of this sequence.

Answer 1

$\huge{\underline{\underline{\sf{AnSweR}}}}$

Let a be the first term and d be the common difference

then in AP :26,19,12,5,-2 ................a(n)ᵗʰ term

Here a =26

and d=a2-a1=19-26=(-7)

we know that

$an = a + (n - 1) \times d$

put the values we get ,

$an = 26 + (n - 1) \times - 7 \\ an = 26 - 7n +7 \\ an = 33 -7n$

therefore nᵗʰ term =33-7n