The front of an aircraft hanger is being built in the shape of a parabola, which is 48 ft. wide, and has a maximum height of 18 ft., AND must have a rectangular doorway that is 8 ft. tall. What is the maximum width of the doorway? (Round your answer to one decimal place.)

Respuesta :

Answer:

maximum width of the doorway = 35.77ft

Explanation:

The detailed calculation and derivation from first principle is as shown in the attachment

Ver imagen olumidechemeng
Ver imagen olumidechemeng

Answer:

the maximum width is x= 4√2 ft = 5.656 ft

Explanation:

for the parabola

y= a*x² + b*x + c

where y= height and x= width

an aircraft hangar should be symmetric with respect to the y axis , then

y(-x)=y(x) → a*x² + b*x + c = a*x² - b*x + c →-2*b*x =0 → b=0

it also should be pointing downwards → a is negative

, then the parabola would be

y= c- a*x²

since c= maximum height = 18 ft

then for y=0 , x= 48 ft/2 = 24 ft  →  0 = 18 ft - a*(24 ft)² → a= 1/32 ft⁻¹

then

y= 18 ft- 1/32 ft⁻¹ *x²

since the doorway cannot go beyond the parabola , the maximum possible doorway is obtained when the doorway touches the parabola.

then for a height y= 8 ft

8 ft = 18 ft- 1/32 ft⁻¹ *x²

x= 4√2 ft = 5.656 ft