Rewrite Integral: Let's first rewrite the integral to make it clearer:∫4xe(−3x+1)dxWe can treat the constant term e1 as a constant multiplier, which can be taken out of the integral. So we rewrite the integral as:4e⋅∫xe(−3x)dxNow we need to apply integration by parts, where we let u=x (which will be differentiated) and dv=e(−3x)dx (which will be integrated).
Integration by Parts: Differentiate u=x to get du=dx. Integrate dv=e−3xdx to get v. To integrate e−3x, we use the fact that the integral of eax is (1/a)eax, so the integral of e−3x is (−1/3)e−3x. Therefore, v=(−1/3)e−3x.
Substitute u, du, v: Now apply the integration by parts formula:∫udv=uv−∫vduSubstitute u, du, v into the formula:∫xe−3xdx=x(−31)e−3x−∫(−31)e−3xdx
Integrate ∫(−31)e−3xdx: Now we need to integrate ∫(−31)e−3xdx. As before, the integral of e−3x is (−31)e−3x, so we get:∫(−31)e−3xdx=(−31)⋅(−31)e−3x=(91)e−3x
Substitute back into formula: Substitute this result back into the integration by parts formula:∫xe−3xdx=x∗(−31)e−3x−(91)e−3xNow we multiply through by the constant 4e from the original integral:4e∗(x∗(−31)e−3x−(91)e−3x)
Simplify the expression: Simplify the expression:4e⋅(x⋅(−31)e−3x−(91)e−3x)=(34e)(−x)e−3x−(94e)e−3xNow we add the constant of integration C to get the final result:(34e)(−x)e−3x−(94e)e−3x+C
More problems from Find indefinite integrals using the substitution and by parts