Skip to main content
A

Anonymous

Jan 23, 2025

What value of θ will maximize the trough’s volume?

What value of θ will maximize the volume of the trough? The trough, as depicted in the accompanying figure, is designed with specific dimensions. The only variable that can be adjusted is the angle θ.

3 Answers

A
Anonymous

Feb 21, 2025

In order to do this, we only really need to know when the trapezoid has the greatest area

9 * cos(t) is the height

4 + 2 * 9 * sin(t) is the 2nd base

A = (1/2) * (b[1] + b[2]) * h

A = (1/2) * (4 + 4 + 18 * sin(t)) * 9 * cos(t)

A = (9/2) * (8 + 18 * sin(t)) * cos(t)

A = (9/2) * 2 * (4 + 9 * sin(t)) * cos(t)

A = 9 * (4 + 9 * sin(t)) * cos(t)

A = 9 * (4 * cos(t) + 9 * sin(t) * cos(t))

A = 9 * (4 * cos(t) + (9/2) * sin(2t))

dA/dt = 9 * (-4 * sin(t) + 9 * cos(2t))

dA/dt = 0

0 = 9 * (-4 * sin(t) + 9 * cos(2t))

0 = 9 * cos(2t) - 4 * sin(t)

4 * sin(t) = 9 * cos(2t)

4 * sin(t) = 9 * (1 - 2 * sin(t)^2)

4 * sin(t) = 9 - 18 * sin(t)^2

18 * sin(t)^2 + 4 * sin(t) - 9 = 0

sin(t) = (-4 +/- sqrt(16 + 36 * 18)) / 36

sin(t) = (-4 +/- 2 * sqrt(4 + 9 * 18)) / 36

sin(t) = (-2 +/- sqrt(4 + 162)) / 18

sin(t) = (-2 +/- sqrt(166)) / 18

sin(t) > 0

(sqrt(166) - 2) / 18

sin(t) = (sqrt(166) - 2) / 18

t = arcsin((sqrt(166) - 2) / 18)

t = 37.20525383385804154732087023355 degrees , 0.64935417844106618398071005902938 radians

A
Anonymous

Feb 17, 2025

The height of the trough is 9*cos(theta).

The horizontal leg of each small triangle is 9*sin(theta).

The area of the rectangle is 36*cos(theta).

The area of the two small triangles together is

81*sin(theta)*cos(theta) or 40.5*sin(2*theta).

The total cross-sectional area of the trough is

A = 36*cos(theta) + 40.5*sin(2*theta).

dA/d(theta) = -36*sin(theta) + 81*cos(2*theta).

Setting this expression to 0, we get

36*sin(theta) = 81*cos(2*theta) =>

4*sin(theta) = 9*[cos^2(theta) - sin^2(theta)] =>

4*sin(theta) = 9*[1 - 2*sin^2(theta)] =>

18*sin^2(theta) + 4*sin(theta) - 9 = 0.

Using the quadratic formula, you have

sin(theta) = -1/9 +/- (1/36)*sqrt(16+648) = +0.60467.

theta = 37.2 degrees.

To see that this makes SOME sense, note that if theta = 45 degrees, the cross-section area is 81/2 + 18*sqrt(2) = about 66; if theta = 30 degrees, the cross-section area is 81*sqrt(3)/4 + 18*sqrt(3) = about 66.25; but if theta = 36.87 degrees (giving 3-4-5 triangles), the area is

972/25 + 3.2*9 = around 67.68...i.e., a little bigger than what you get for theta = 30 or 45.

A
Anonymous

Feb 10, 2025

find the Θ which yields max area of the end...if the height is x then the the top is 4 + 2 [ 9 sin Θ ] where

x = 9 cos Θ...thus A = [ base 1 + base 2] / 2 [ height ] = [4 + 9 sin Θ ] [ 9 cos Θ ] =

36 cos Θ + 81 sin Θ cos Θ ====> - 36 sin Θ + 81[ cos² Θ - sin² Θ ] = 0...let w = sin Θ

- 36 w + 81 [ 1 - 2 w² ] = 0 ===> w = you finish

Want to answer this question?

Join our community to share your knowledge!

Related Questions

3
Find the circumference of p. leave your answer in terms of pi. the radious is 5 in.

Find the circumference of a circle with a radius of 5 inches. Please express your answer in terms of pi.

3
how tall is 77 inches in feet?

How tall is 77 inches when converted to feet?

3
In circle O, ST is a diameter. What must be the value of x?

In circle O, ST is a diameter. What is the value of x if (2x + 8) equals one of the following options: 22.0, 25.0, 25.4,...

2
Suppose there are two known compounds containing generic x and y. you have a 1.00g sample of each compound.

Suppose there are two known compounds containing the elements x and y, and you have a 1.00 g sample of each compound. Wh...

3
what is the hybridization of phosphorus atom in PCl3?

What is the hybridization of the phosphorus atom in PCl3? Additionally, could you please provide an explanation of the s...

2
a question regarding torque in a magnetism setting?

I have a question regarding torque in a magnetism context. I understand that the equation τ = IABsin(θ) will be relevant...

2
Find the cube roots of 8(cos 216° + i sin 216°).

Could you please help me find the cube roots of the complex number represented in polar form as 8(cos 216° + i sin 216°)...

1
Present and future values for different interest rates find the following values. compounding/discounting occurs annually. round your

Please find below the present and future values for different interest rates. Compounding and discounting occur annually...

2
What is the hybridization on the central atom in CH2F2 and in COF2?

What is the hybridization of the central atom in the molecules CH2F2 (difluoromethane) and COF2 (carbonyl fluoride)? Add...

10
what is the speed of light (in kilometers an hour)?

What is the speed of light in kilometers per hour?