Answer:
Explanation:
Alright so the way to do this is to use properties of integrals to make our life easier.
So we have:

So lets break this up into two different integrals that represent the same area.

Lets think about what is going on up there. The integral from four to zero gives us the area under the curve of f(x) from four to zero. If we subtract this from the integral from one to zero (the area under f from one to zero) we are left with the area under f from four to one! Hence:

But since we have these values we can say that: 
-3 - 2 = -5 
Which means that 
 = -5
So now we can evaluate 
Lets first break up our integrand into two integrals 
 = 
Now we can evaluate this:
We know that 
 = -5
So:
 where x is evaluated at 4 to 1 so
-15 + 2(3)
So we are left with -15 + 6 = -9
 
        
             
        
        
        
Because they didn’t have the means to see past the milky way
        
             
        
        
        
By using a woodstove, the kilograms of wood required to
heat a room to 20°C is 3 kg
<h3>Efficiency of a machine</h3>
- Efficiency is the percent of work put into a machine (input work) to that of the work done by the machine (output work). 
 
- Efficiency of a machine is always less than 100% because the output work is always less than the input work because some of the input work is used to overcome friction.
 
Efficiency = work output/work input * 100%
Efficiency of fireplaces = 15%
Amount of food required to heat a room to 20°C = 15 kg
Assuming efficiency of 100%, amount of wood required will be X kg:
X = 15% * 15 kg
X = 2.25 Kg
By switching to woodstoves which are 75% efficient, amount of wood required will be Y kg:
Y = 2.25 kg / 75%
Y = 3 kg
Therefore, by using a woodstove, the kilograms of wood required to
heat a room to 20°C is 3 kg
Learn more about efficiency of machines at: brainly.com/question/3617034