When considering the normal power demand as reported by a utility company, the power demand at midnight is 1040 mw. during the first five hours, the power demand rises to 1600 mw, and at the eight-hour mark, the power demand rises to 1960 mw. what is the average rate of change of the power demand with respect to time for the period from 5 hours to 8 hours after midnight? 360 mw 282.5 mw/hour 120 mw/hour 1780 mw/hour none of these

120 MW/hour

Step-by-step explanation:

The formula of the average rate of change between two points in a function is:

Average rate of change (ARC) = f(x2) -f(x1)/(x2-x1)

Let's think  the power demad as a function d(x) depending of the hour of the day, so the variable x= hour of the day.

Now we have:

d(5)= 1600

d(8)= 1960

If we apply the mentioned ARC formula = [d(8)-d(5)] MW/(8-5)hour= (1960-1600)MW/3hour= 360/3=120 MW/Hour

let's add {f(x)=x+1}f(x)=x+1 and {g(x)=2x}g(x)=2x together to make a new function.

f(x)+g(x) =(x+1)+(2x)=x+1+2x=3x+1

let's call this new function hh. so we have:

{h(x)}={f(x)}+{g(x)}{=3x+1}h(x)=f(x)+g(x)=3x+1

we can also evaluate combined functions for particular inputs. let's evaluate function hh above for x=2x=2. below are two ways of doing this.

method 1: substitute x=2x=2 into the combined function hh.

h(x)

h(2)

​    

=3x+1

=3(2)+1

=7

​ since h(x)=f(x)+g(x)h(x)=f(x)+g(x), we can also find h(2)h(2) by finding f(2) +g(2)f(2)+g(2).

first, let's find f(2)f(2):

f(x)

f(2)

​    

=x+1

=2+1

=3

​  

now, let's find g(2)g(2):

g(x)

g(2)

​    

=2x

=2⋅2

=4

​  

so f(2)+g(2)=3+4=\greend7f(2)+g(2)=3+4=7.

notice that substituting x =2x=2 directly into function hh and finding f(2) + g(2)f(2)+g(2) gave us the same answer!

47 - 90 = 43

43 - 180 = x

x = 137