Originally Posted by

**centenial** Hi,

I'm learning about sequences and series in my calc 2 textbook. I have a question about this definition:

A sequence {$\displaystyle a_n$} is called **increasing** if {$\displaystyle a_n$} < {$\displaystyle a_{n+1}$} for all $\displaystyle n \geq 1$. It is called **decreasing** if {$\displaystyle a_n$} > {$\displaystyle a_{n+1}$} for all $\displaystyle n \geq 1$. It is called **monotonic** if it is either increasing or decreasing.

Should that read "if it is *neither* increasing or decreasing." ?

It looks like a typo, but I'm not sure, so I thought I would ask for clarification. I tried some google searches but couldn't find a clear definition.

Thanks!