Consider the function f ( x ) {\displaystyle f(x)} (solid curve) and its tangent line at x = 4 {\displaystyle x=4} (dashed). The graph of f ( x ) {\displaystyle f(x)} is symmetric about x = 2 {\displaystyle x=2} . Calculate the quantities below.
(a) lim h → 0 f ( 4 + h ) − f ( 4 ) h {\displaystyle \lim _{h\to 0}{\frac {f(4+h)-f(4)}{h}}}
