Question
what is the derivative of $$\left| {x - 1} \right|$$ at $$x = 2\,?$$
A.
$$ - 1$$
B.
$$0$$
C.
$$1$$
D.
Derivative does not exist
Answer :
$$1$$
Solution :
$$f\left( x \right) = \left| {x - 1} \right|$$
Redefined the function $$f\left( x \right)$$
\[\begin{array}{l}
f\left( x \right) = \left\{ \begin{array}{l}
1 - x,\,\,\,\,\,x < 1\\
x - 1,\,\,\,\,\,x > 1
\end{array} \right.\\
f'\left( x \right) = \left\{ \begin{array}{l}
- 1\,;\,\,\,\,\,x < 1\\
\,\,\,1\,;\,\,\,\,\,x > 1
\end{array} \right.\\
\therefore f'\left( 2 \right) = 1
\end{array}\]