Question

Which of the following is not an arithmetic sequence?
a.3,7,11,15
b.-1,-8,-15,-22
c.2,6,12,24
d.-1,5,11,17

Answer 1

$\underline{\textsf{Given:}}$

$\textsf{a.3,7,11,15...}$

$\textsf{b.-1,-8,-15,-22.....}$

$\textsf{c.2,6,12,24.....}$

$\textsf{d.-1,5,11,17....}$

$\underline{\textsf{To find:}}$

$\textsf{Whether the above sequeuences arithmetic or not}$

$\underline{\textsf{Solution:}}$

$\textsf{Consider,}$

$\textsf{a.3,7,11,15...}$

$\textsf{Here, the differences are equal}$

$\textsf{This is an arithmetic sequence with common difference 4}$

$\textsf{b.-1,-8,-15,-22...}$

$\textsf{Here, the differences are equal}$

$\textsf{This is an arithmetic sequence with common difference -7}$

$\textsf{c.2,6,12,24...}$

$\textsf{Here, the differences are not equal}$

$\textsf{This is not an arithmetic sequence}$

$\textsf{d.-1,5,11,17...}$

$\textsf{Here, the differences are equal}$

$\textsf{This is an arithmetic sequence with common difference 6}$