Recognize Integral Type: Recognize that the integral involves a logarithmic function multiplied by a power of x. This suggests that integration by parts may be a useful technique. The integration by parts formula is ∫udv=uv−∫vdu.
Choose u and dv: Choose u and dv for the integration by parts. Let u=ln(5x) and dv=−x−3dx. Then we need to compute du and v. Differentiating u gives du=(1/x)dx, and integrating dv gives dv1.
Compute du and v: Compute du and v. We have du=dxd(ln(5x))⋅dx=(x1)dx and v=∫−x−3dx=(21)x−2.
Apply Integration by Parts: Apply the integration by parts formula. We have ∫−x−3ln(5x)dx=uv−∫vdu=ln(5x)(21x−2)−∫(21x−2)(x1)dx.
Simplify Integral: Simplify the integral ∫(21)x−2(x1)dx. This simplifies to (21)∫x−3dx.
Integrate Simplified Integral: Integrate (21)∫x−3dx. The integral of x−3 with respect to x is −21×x−2.
Combine Integration Results: Combine the results from integration by parts. We have ln(5x)⋅21x−2−21(−21⋅x−2)=21x−2ln(5x)+41x−2.
Add Constant of Integration: Add the constant of integration C to the result. The final answer is (21)x−2ln(5x)+(41)x−2+C.
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