Question

The graph shows a function that models the value V (in millions of dollars) of a stock portfolio as a function of time t (in months) over an 18-month period.

Answer 1

(a)

$0\leq t\leq 4$

we can see that

curve is moving upward from t=0 to t=4

so, this is increasing interval.........Answer

(b)

$15\leq t\leq 18$

we can see that

curve is moving upward from t=15 to t=18

so, this is increasing interval.........Answer

(c)

$4\leq t\leq 15$

we can see that

curve is moving downward from t=4 to t=15

so, this is decreasing interval.........Answer