Q.If $f(x) = |x - 2| + |x + 2|$, find $f(-3)$, $f(0)$ and $f(3)$.

These three standard real functions are each defined piecewise rather than by one algebraic expression. The modulus function $f(x)=|x|$ gives the non-negative magnitude of $x$ (domain $\mathbb{R}$, range $[0,\infty)$) and its graph is a V-shaped pair of $45°$ rays meeting at the origin. The signum function reduces $x$ to just its sign, $1$, $0$ or $-1$ (domain $\mathbb{R}$, range $\{-1,0,1\}$), graphed as three disconnected horizontal pieces. The greatest integer f …