Answer:
Therefore F=2.387 hours gives a minimum value of energy expenditure E.
Step-by-step explanation:
Given that,
The energy expended by a bird per day
[tex]E=0.25 F+\frac{1.7}{F^2}[/tex]
Differentiating with respect to F
[tex]E'=0.25 -\frac{3.4}{F^3}[/tex]
Again differentiating with respect to F
[tex]E''=\frac{10.2}{F^4}[/tex]
Now set E'=0
[tex]0.25 -\frac{3.4}{F^3}=0[/tex]
[tex]\Rightarrow \frac{3.4}{F^3}=0.25[/tex]
[tex]\Rightarrow F^3=\frac{3.4}{0.25}[/tex]
[tex]\Rightarrow F=2.387[/tex]
Now [tex]E''|_{F=2.387}=\frac{10.2}{2.387^4}>0[/tex]
Since, E''>0 at F=2.387, So at F=2.387 , E has minimum value.
Therefore F=2.387 hours that minimizes energy expenditure.