Question Detail

MTH 102 MTH 102 Past Questions Objective Question

Question

Find the area between the curve y = x³ - 6x² + 8x and the x-axis in square units.
Options
A 8
Correct Answer
B -8
C 0
D 16
Correct Answer

Option A is the correct answer.

Detailed Explanation

First, find the x-intercepts by setting y = 0:x³ - 6x² + 8x = 0x(x² - 6x + 8) = 0x(x - 2)(x - 4) = 0The x-intercepts are x = 0, x = 2, x = 4.The area is calculated by integrating the absolute value of the function over the intervals defined by the intercepts.The function y = x(x-2)(x-4) is positive between 0 and 2, and negative between 2 and 4.Area = ∫₀² (x³ - 6x² + 8x) dx + |∫₂⁴ (x³ - 6x² + 8x) dx|Find the indefinite integral: ∫ (x³ - 6x² + 8x) dx = x⁴/4 - 2x³ + 4x². Let F(x) = x⁴/4 - 2x³ + 4x².For the first interval [0, 2]:F(2) - F(0) = (2⁴/4 - 2(2)³ + 4(2)²) - (0) = (16/4 - 16 + 16) = 4.For the second interval [2, 4]:F(4) - F(2) = (4⁴/4 - 2(4)³ + 4(4)²) - (4) = (64 - 128 + 64) - 4 = 0 - 4 = -4.Total Area = 4 + |-4| = 4 + 4 = 8.

Hint

First, find the x-intercepts of the function to determine the integration intervals. Then, integrate the function over each interval and sum the absolute values of the results to find the total area.

Question Info