Let region be the set of points in the -plane that satisfy
MATHEMATICS · Multi-part · AP · Calculus AB · Applications of Integration · Applications of Integration
Problem
Let region R be the set of points in the xy-plane that satisfy ∣x∣≤y≤4. A solid has R as its base. For every y with 0≤y≤4, a cross section perpendicular to the y-axis is erected.
• For 0≤y≤2, each cross section is a square.
• For 2≤y≤4, each cross section is a rectangle whose height is three times the length of its base.
Complete the tasks below. Clearly communicate your reasoning.
(1) Part 1: (a) Explain why the width w(y) of the base segment at a fixed value of y is 2y.
(2) Part 2: (b) Derive an explicit expression for the area A1(y) of a square cross section when 0≤y≤2.
(3) Part 3: (c) Write, then evaluate, a definite integral that gives the volume V1 contributed by the square cross sections.
(4) Part 4: (d) Derive an explicit expression for the area A2(y) of a rectangular cross section when 2≤y≤4.
(5) Part 5: (e) Write, then evaluate, a definite integral that gives the volume V2 contributed by the rectangular cross sections. State the total volume of the solid, using proper units.