The polynomial function y = -0.005x4 + 0.05x3 – 0.086x2 – 0.04x + 2.52 represents the fluctuating gas price (in dollars per gallon) in a city over the course of 6 years. Calculate the average rate of change from year 0 to year 2, and then calculate the average rate of change from year 3 to year 6.

Respuesta :

Answer:

Part a) The average rate of change is -0.052

part b) The average rate of change is 0.311

Step-by-step explanation:

we have

[tex]y=-0.005x^4+0.05x^3-0.086x^2-0.04x+2.52[/tex]

we know that

the average rate of change is equal to

[tex]\frac{f(b)-f(a)}{b-a}[/tex]

Part a) Calculate the average rate of change from year 0 to year 2

In this problem we have

[tex]a=0[/tex]

[tex]b=2[/tex]

[tex]f(a)=f(0)=-0.005(0)^4+0.05(0)^3-0.086(0)^2-0.04(0)+2.52=2.52[/tex]  

[tex]f(b)=f(2)=-0.005(2)^4+0.05(2)^3-0.086(2)^2-0.04(2)+2.52=2.416[/tex]

Substitute

[tex]\frac{2.416-2.52}{2-0}=-0.052[/tex]

Part b) Calculate the average rate of change from year 3 to year 6

In this problem we have

[tex]a=3[/tex]

[tex]b=6[/tex]

[tex]f(a)=f(3)=-0.005(3)^4+0.05(3)^3-0.086(3)^2-0.04(3)+2.52=2.571[/tex]  

[tex]f(b)=f(6)=-0.005(6)^4+0.05(6)^3-0.086(6)^2-0.04(6)+2.52=3.504[/tex]

Substitute

[tex]\frac{3.504-2.571}{6-3}=-0.311[/tex]