
(a)
![f'(x) = \frac{d}{dx}[\frac{lnx}{x}]](https://tex.z-dn.net/?f=f%27%28x%29%20%3D%20%5Cfrac%7Bd%7D%7Bdx%7D%5B%5Cfrac%7Blnx%7D%7Bx%7D%5D)
Using the quotient rule:


For maximum, f'(x) = 0;


(b) <em>Deduce:
</em>

<em>
Soln:</em> Since x = e is the greatest value, then f(e) ≥ f(x) > f(0)


, since ln(e) is simply equal to 1
Now, since x > 0, then we don't have to worry about flipping the signs when multiplying by x.



Taking the exponential to both sides will cancel with the natural logarithmic function in the right hand side to produce:


, as required.
Answer:
V(cylinder) = πr²h
h=3 cm
r=2 cm
V(cylinder) = πr²h = π*2²*3 =12π cm³
Answer : 12π cm³.
The answer would be -4.5/5. You would have to plot the number in between -2 and - 1 4/5. Hope this helps!
The least number of books that could be in the box is 30. The number of books in the box could be any number that is a multiple of 30.
set up the triangle with the information given. then just solve for x.