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  1. AP Calculus
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Volume of a solid with known cross-sections.

V=∫abA(x)dxV = \int_a^b A(x) dxV=∫ab​A(x)dx

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Volume of a solid with known cross-sections.

V=∫abA(x)dxV = \int_a^b A(x) dxV=∫ab​A(x)dx

Volume of a solid with square cross-sections.

V=∫abs2dxV = \int_a^b s^2 dxV=∫ab​s2dx

Volume of a solid with rectangular cross-sections.

V=∫abwcdothdxV = \int_a^b w cdot h dxV=∫ab​wcdothdx

Area of a square.

A=s2A = s^2A=s2

Area of a rectangle.

A=wcdothA = w cdot hA=wcdoth

How do you find the side length 's' of a square cross section when given two bounding curves f(x) and g(x), where f(x) is above g(x)?

s=f(x)−g(x)s = f(x) - g(x)s=f(x)−g(x)

How do you find the width 'w' of a rectangular cross section perpendicular to the y-axis when given two bounding curves f(y) and g(y), where f(y) is to the right of g(y)?

w=f(y)−g(y)w = f(y) - g(y)w=f(y)−g(y)

How to find the intersection points of two curves, f(x)f(x)f(x) and g(x)g(x)g(x)?

Set f(x)=g(x)f(x) = g(x)f(x)=g(x) and solve for xxx.

If integrating with respect to 'y', what does the volume formula become for general cross sections?

V=∫cdA(y)dyV = \int_c^d A(y) dyV=∫cd​A(y)dy

How do you express y=x3y = x^3y=x3 as a function of y?

x=y3x = \sqrt[3]{y}x=3y​

Steps to find the volume of a solid with square cross-sections given two bounding curves.

  1. Find the intersection points of the curves (bounds). 2. Determine the side length s=f(x)−g(x)s = f(x) - g(x)s=f(x)−g(x). 3. Square the side length: A(x)=s2A(x) = s^2A(x)=s2. 4. Integrate: V=∫abA(x)dxV = \int_a^b A(x) dxV=∫ab​A(x)dx.

Steps to find the volume of a solid with rectangular cross-sections perpendicular to the y-axis.

  1. Express bounding curves as functions of y. 2. Find the intersection points (bounds). 3. Determine width and height as functions of y. 4. Find area: A(y)=w∗hA(y) = w*hA(y)=w∗h. 5. Integrate: V=∫cdA(y)dyV = \int_c^d A(y) dyV=∫cd​A(y)dy.

How to find the volume of a solid with square cross sections if given y=x2y = x^2y=x2 and y=4y = 4y=4?

  1. Find bounds: x=−2,2x = -2, 2x=−2,2. 2. s=4−x2s = 4-x^2s=4−x2. 3. A(x)=(4−x2)2A(x) = (4-x^2)^2A(x)=(4−x2)2. 4. V=∫−22(4−x2)2dxV = \int_{-2}^2 (4-x^2)^2 dxV=∫−22​(4−x2)2dx.

How to set up the integral for the volume of a solid with rectangular cross sections of height 3, perpendicular to the x-axis, bounded by y=xy = xy=x and y=x2y = x^2y=x2?

  1. Find bounds: x=0,1x = 0, 1x=0,1. 2. w=x−x2w = x - x^2w=x−x2. 3. h=3h = 3h=3. 4. V=∫013(x−x2)dxV = \int_0^1 3(x - x^2) dxV=∫01​3(x−x2)dx.

How to find the volume if the base is bounded by y=x3y=x^3y=x3, y=0y=0y=0, x=1x=1x=1 and the cross sections are squares perpendicular to the x-axis?

  1. Find bounds: x=0,1x = 0, 1x=0,1. 2. s=x3−0=x3s = x^3 - 0 = x^3s=x3−0=x3. 3. A(x)=(x3)2=x6A(x) = (x^3)^2 = x^6A(x)=(x3)2=x6. 4. V=∫01x6dxV = \int_0^1 x^6 dxV=∫01​x6dx.

How to find the volume if the base is bounded by x=y2x=y^2x=y2, x=4x=4x=4 and the cross sections are rectangles with height yyy perpendicular to the y-axis?

  1. Find bounds: y=−2,2y = -2, 2y=−2,2. 2. w=4−y2w = 4 - y^2w=4−y2. 3. h=yh = yh=y. 4. V=∫−22y(4−y2)dyV = \int_{-2}^2 y(4 - y^2) dyV=∫−22​y(4−y2)dy.

How do you determine the limits of integration when the region is bounded by y=x2y = x^2y=x2 and y=sqrtxy = sqrt{x}y=sqrtx?

Set x2=xx^2 = \sqrt{x}x2=x​ and solve for xxx to find the intersection points, which are the limits of integration.

What is the general strategy for solving volume problems with known cross-sections?

  1. Visualize the solid. 2. Determine the shape and area of the cross-section. 3. Find the limits of integration. 4. Set up and evaluate the integral.

If the cross-sections are perpendicular to the y-axis, how do you express the bounding curves?

Express the curves as functions of y, i.e., x=f(y)x = f(y)x=f(y) and x=g(y)x = g(y)x=g(y).

How do you handle a problem where the height of the rectangular cross-section is given as a function of x?

Include the height function in the area function A(x)=w(x)cdoth(x)A(x) = w(x) cdot h(x)A(x)=w(x)cdoth(x) and integrate with respect to x.

Explain how to find the volume of a solid with known cross-sections.

Integrate the area function A(x)A(x)A(x) of the cross-sections over the interval [a,b][a, b][a,b].

Describe the relationship between the area of a cross-section and the volume of a solid.

The volume is the accumulation of the areas of infinitely thin cross-sections.

Explain why we use integration to find the volume of a solid with known cross-sections.

Integration sums the areas of infinitely many infinitesimally thin slices to find the total volume.

When finding volumes with cross sections, why is it important to determine the correct bounds of integration?

The bounds define the region over which the volume is calculated; incorrect bounds lead to an incorrect volume.

Explain the difference between integrating with respect to x and integrating with respect to y when finding volumes.

Integrating with respect to x uses cross-sections perpendicular to the x-axis; integrating with respect to y uses cross-sections perpendicular to the y-axis.

Describe how visualizing the solid can help in solving volume problems.

Visualization helps determine the shape of the cross-sections, the limits of integration, and the correct formula for the area function.

What is the role of the curves that bound the base of the solid?

They define the dimensions (side length, width, height) of the cross-sections.

Explain how the orientation of the cross-sections (perpendicular to x or y axis) affects the setup of the integral.

Orientation determines whether to integrate with respect to x or y, and how the area function A(x) or A(y) is defined.

Explain the concept of finding the area between two curves.

It involves integrating the difference between the upper and lower curves over a given interval.

Describe the steps to find the volume of a solid with square cross-sections.

Find the side length s, square it to get the area A(x), and integrate A(x) over the interval [a, b].