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some airlines have restrictions on the size of items of luggage that passengers are allowed to take with them. suppose that one has a rule that the sum of the length, width and height of any piece of luggage must be less than or equal to 234 cm. a passenger wants to take a box of the maximum allowable volume. if the length and width are to be equal, what should the dimensions be?

Respuesta :

The length, breadth and height will be 78 cm, 78cm, 78cm each.

let consider the length = l

breadth = b

height = h

we are provided that

l + b + h = 234cm .......(1)

Also we have to maximize the volume , provided length is equal to breadth

∴ eqn (1) becomes

2b + h = 234

h = 234 - 2b

also ,

volume(v) = lbh

v = b²(234 - 2b)

v = b²234 - 2b³

now to maximize the volume we take the first derivative of the volume wrt 'b' and place it equal to zero. ( lagrange method )

i.e. d( v)/db = 0

∴  468b - 6b² = 0

 6b² - 468b = 0

6b( b - 78 ) = 0

∴  b = 78 cm

now as length = breadth

l = b = 78 cm

also putting this value in eqn (1)

h = 234 - 2b

h =  78 cm

So , the dimensions will be equal and will be 78cm , 78cm, 78cm each .

learn more about lagrange method here :

https://brainly.com/question/24208980

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