Answer
(a) Yes.
(b) $[0,24]$
(c) $1200\ MW$
(d) maximum at 5 P.M. minimum at 4 A.M.
(e) $f(12)=1900\ MW$
(f) Increasing $(4,17)\ hr$, decreasing $(0,4)U(17,24)\ hr$
Work Step by Step
(a) The graph is a function because it will pass the vertical line test.
(b) Its domain is a collection of x-values which is $[0,24]$
(c) Start from 8 A.M. go upwards to meet the curve read the vertical coordinate as $1200\ MW$
(d) The maximum happens at about 17 hr or 5 P.M. and the minimum happens at about 4 A.M.
(e) Start from 12 noon, go upwards to meet the curve, read its vertical value as $f(12)=1900\ MW$
(f) Increasing intervals $(4,17)\ hr$, decreasing intervals $(0,4),(17,24)\ hr$
