Answer: B
Step-by-step explanation:

(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: 300 ml
Step-by-step explanation:
First and foremost, we should note that:
1000 milliliters = 1 liter
Therefore, 2.1 liters = 2.1 × 1000 = 2100 millimeters.
Therefore, since the liters of water is divided into 7 containers, the vlaue in each container will be:
= 2100 millimeters / 7
= 300 millimeters
Answer:
A. t(x) = 450 - 0.06x
Step-by-step explanation:
The layer which is originally 450 m thick is decreasing by 0.06 m.
450 - 0.06
... per day. x represents days.
0.06x
So,
450 - 0.06x