Integration by Parts: We will use integration by parts to evaluate the integral of −x2e2x with respect to x. Integration by parts is given by the formula ∫udv=uv−∫vdu, where u and dv are parts of the integrand that we choose. We will let u=−x2 (which means du=−2xdx) and dv=e2xdx (which means v=(1/2)e2x). Now we will calculate du and x0.
Calculate u and v: First, we calculate du by differentiating u=−x2. The derivative of −x2 with respect to x is −2x, so du=−2xdx.
Apply Integration by Parts: Next, we find v by integrating dv=e2xdx. The integral of e2x with respect to x is (1/2)e2x, so v=(1/2)e2x.
Simplify the Expression: Now we apply the integration by parts formula: ∫udv=uv−∫vdu. Substituting the values of u, v, and du, we get:∫−x2e2xdx=(−x2)(21)e2x−∫(21)e2x(−2x)dx.
Integrate by Parts Again: Simplify the expression: ∫−x2e2xdx=(−21)x2e2x−∫−xe2xdx.
Calculate du and v: We need to integrate −xe2xdx again by parts. Let u=−x (which means du=−dx) and dv=e2xdx (which means v=(1/2)e2x). We calculate du and v again.
Apply Integration by Parts Again: Calculate du by differentiating u=−x. The derivative of −x with respect to x is −1, so du=−dx.
Simplify the Expression: Find v by integrating dv=e2xdx again. As before, the integral of e2x with respect to x is (21)e2x, so v=(21)e2x.
Integrate (21)e(2x)dx: Apply the integration by parts formula again: ∫udv=uv−∫vdu. Substituting the new values of u, v, and du, we get: ∫−xe(2x)dx=(−x)(21)e(2x)−∫(21)e(2x)(−1)dx.
Combine All Parts: Simplify the expression:∫−xe2xdx=(−21)xe2x+(21)∫e2xdx.
Final Answer: Now we integrate (21)e(2x)dx. The integral of e(2x) with respect to x is (21)e(2x), so we get:(21)∫e(2x)dx=(21)(21)e(2x)=(41)e(2x).
Final Answer: Now we integrate (21)e(2x)dx. The integral of e(2x) with respect to x is (21)e(2x), so we get:(21)∫e(2x)dx=(21)(21)e(2x)=(41)e(2x).Combine all the parts together to get the final answer:∫−x2e(2x)dx=(−21)x2e(2x)−((−21)xe(2x)+(41)e(2x))+C, where C is the constant of integration.
Final Answer: Now we integrate (1/2)e(2x)dx. The integral of e(2x) with respect to x is (1/2)e(2x), so we get:(1/2)∫e(2x)dx=(1/2)(1/2)e(2x)=(1/4)e(2x).Combine all the parts together to get the final answer:∫−x2e(2x)dx=(−1/2)x2e(2x)−((−1/2)xe(2x)+(1/4)e(2x))+C, where C is the constant of integration.Simplify the expression to get the final answer:∫−x2e(2x)dx=(−1/2)x2e(2x)+(1/2)xe(2x)−(1/4)e(2x)+C.
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