AP Calculus AB Exam Question:
Determine the area of the region bounded by the curves π¦ = π₯^2 and π¦ = 2π₯.
Step-by-step Solution:
To find the area between two curves, we need to locate the points where they intersect first.
Setting the two equations equal to each other, we can find the x-values of the intersection points:
π₯^2 = 2π₯
Rearranging the equation:
π₯^2 - 2π₯ = 0
Factoring out an π₯:
π₯(π₯ - 2) = 0
Therefore, the two intersection points are π₯ = 0 and π₯ = 2.
Next, we need to determine the limits of integration. Since π¦ = π₯^2 is below π¦ = 2π₯ in the interval [0, 2], the limits of integration will be 0 and 2.
Now, we want to find the area between the curves, so we'll evaluate the definite integral:
β«[0,2] (2π₯ - π₯^2) ππ₯
Expanding the integrand, we have:
β«[0,2] (2π₯)ππ₯ - β«[0,2] (π₯^2)ππ₯
Integrating each term separately:
β«[0,2] (2π₯)ππ₯ = π₯^2 |[0,2] = (2^2) - (0^2) = 4 - 0 = 4
β«[0,2] (π₯^2)ππ₯ = (1/3)π₯^3 |[0,2] = (1/3)(2^3) - (1/3)(0^3) = (1/3)(8) - (0) = 8/3
Substituting the integration results back into the original integral, we have:
4 - 8/3 = 12/3 - 8/3 = 4/3
Therefore, the area between the curves π¦ = π₯^2 and π¦ = 2π₯ in the interval [0, 2] is 4/3 square units.