A solid has base region lying on the -axis between and

MATHEMATICS · Multi-part · AP · Calculus AB · Applications of Integration · Applications of Integration

Problem

A solid has base region TT lying on the xx-axis between x=−2x = -2 and x=3x = 3. The lower boundary of TT is the xx-axis. The upper boundary is piecewise defined by  y=x+3y = x + 3  for −2≤x≤0-2 \le x \le 0,  y=3y = 3    for 0≤x≤30 \le x \le 3. At each xx in [−2,3][-2, 3], a cross section perpendicular to the xx-axis is constructed; the cross sections are rectangles whose height (in units) is given by h(x)=1+2e−xh(x) = 1 + 2e^{-x}. Respond to the following prompts, showing complete justification. (1) Part 1: (a) For −2≤x≤0-2 \le x \le 0, write an explicit expression for the base length b1(x)b_1(x) of a cross section. (2) Part 2: (b) For 0≤x≤30 \le x \le 3, write an explicit expression for the base length b2(x)b_2(x) of a cross section. (3) Part 3: (c) Formulate a definite integral for the volume V1V_1 coming from the interval −2≤x≤0-2 \le x \le 0, and a separate definite integral for the volume V2V_2 coming from the interval 0≤x≤30 \le x \le 3. Do not evaluate yet. (4) Part 4: (d) Evaluate both integrals from part (c) exactly, and obtain the total volume of the solid. Express your answer in exact form, simplifying as far as possible.

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