Answer:
Required largest volume is 0.407114 unit.
Step-by-step explanation:
Given surface area of a right circular cone of radious r and height h is,
and volume,

To find the largest volume if the surface area is S=8 (say), then applying Lagranges multipliers,
subject to,

We know for maximum volume
. So let
be the Lagranges multipliers be such that,



And,



Substitute (3) in (2) we get,



Substitute this value in (1) we get,



Then,

Hence largest volume,

Step-by-step explanation:
ATQ,
Let d be the number of kilograms of dark chocolate she buys and m be the number of kilograms of milk chocolate she buys.
She needs to buy 120 kg of chocolate in total for her next order, and her recipe calls for twice the amount of dark chocolate as milk chocolate.
So,
m = 2d .....(1)
m + d = 120 ...(2)
We can also solve the above equations,
Put m = 2d in equation (2)
2d + d = 120
3d=120
d = 40
Put d = 40 in equation (1)
m = 2(40)
m = 80
Hence, she will need 40 kg of dark chocolate and 80 kg of milk chocolate.