Let $A\xrightarrow{u} B\xrightarrow{v} C\xrightarrow{w} A[-1]$ be an exact triangle.
Consider rotation $B\xrightarrow{v} C\xrightarrow{w} A[-1]\xrightarrow{-u[-1]} B[-1]$ and $C[1]\xrightarrow{-w[1]}A\xrightarrow{u}B\xrightarrow{v} C$
$\textbf{Q:}$ Why $A[-1]\to B[-1]$'s morphism is $-u[-1]$? Should this not be $u[-1]$ only? Similarly why $C[1]\to A$ is $-w[1]$ instead of $w[1]$?
Ref. Weibel, Homological Algebra, Chpt 10, Example 10.1.6(Rotation)