Q:

Graph the function y = 2x3 – x2 – 4x + 5. To the nearest tenth, over which interval is the function decreasing?(1, ∞)(–∞, –0.7)(–0.7, 1)(–1, 0.7)

Accepted Solution

A:
Answer:Option 3 - (-0.7,1)   Step-by-step explanation:Given : Function  [tex]y=2x^3-x^2-4x+5[/tex]To find : Over which interval is the function decreasing? Solution : First we plot the graph using graphing calculator.Refer the attached figure below.Now, Examining the graphFrom [tex]-\infty[/tex] to (-0.667,6.63) the graph is increasing as the curve is increasing.From (-0.667,6.63) to (1,2) the graph decreasing as the curve is decreasing.From  (1,2) to [tex]\infty[/tex] the graph is increasing as the curve is increasing.So, The interval in which the function is decreasing is given by (-0.667,1)Round to nearest tenth,  (-0.7,1)Therefore, Option 3 is correct.