Given Integral: We are given the integral to evaluate: ∫−22(x3cos(2x)+21)4−x2dx This integral can be split into two separate integrals: ∫−22x3cos(2x)dx+∫−22214−x2dx
First Integral: First, let's focus on the first integral:∫−22x3cos(2x)dxThis integral does not have an elementary antiderivative, and it is an odd function over a symmetric interval around zero. Since the cosine function is even and x3 is odd, their product is an odd function. The integral of an odd function over a symmetric interval around zero is zero.Therefore, ∫−22x3cos(2x)dx=0
Second Integral: Now, let's focus on the second integral:∫−22214−x2dxThis integral represents the area of a semicircle with radius 2, because the integrand is the equation of a semicircle in the upper half-plane.The area of a semicircle is given by (1/2)πr2, where r is the radius.
Area Calculation: Since the radius r is 2, we can calculate the area of the semicircle:Area = (1/2)π(2)2Area = (1/2)π(4)Area = 2πTherefore, ∫−22214−x2dx=2π
Final Result: Adding the results of the two integrals together, we get: 0 (from the first integral) + 2π (from the second integral) = 2π
More problems from Evaluate definite integrals using the chain rule