Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

Evaluate the integral.

int-x^(-3)ln(5x)dx
Answer:

Evaluate the integral.\newlinex3ln(5x)dx \int-x^{-3} \ln (5 x) d x \newlineAnswer:

Full solution

Q. Evaluate the integral.\newlinex3ln(5x)dx \int-x^{-3} \ln (5 x) d x \newlineAnswer:
  1. Recognize Integral Type: Recognize that the integral involves a logarithmic function multiplied by a power of xx. This suggests that integration by parts may be a useful technique. The integration by parts formula is udv=uvvdu\int u \, dv = uv - \int v \, du.
  2. Choose uu and dvdv: Choose uu and dvdv for the integration by parts. Let u=ln(5x)u = \ln(5x) and dv=x3dxdv = -x^{-3}dx. Then we need to compute dudu and vv. Differentiating uu gives du=(1/x)dxdu = (1/x)dx, and integrating dvdv gives dvdv11.
  3. Compute du and v: Compute du and v. We have du=d(ln(5x))dxdx=(1x)dxdu = \frac{d(\ln(5x))}{dx} \cdot dx = \left(\frac{1}{x}\right)dx and v=x3dx=(12)x2v = \int -x^{-3}dx = \left(\frac{1}{2}\right)x^{-2}.
  4. Apply Integration by Parts: Apply the integration by parts formula. We have x3ln(5x)dx=uvvdu=ln(5x)(12x2)(12x2)(1x)dx\int -x^{-3}\ln(5x)\,dx = uv - \int v\,du = \ln(5x)\left(\frac{1}{2}x^{-2}\right) - \int\left(\frac{1}{2}x^{-2}\right)\left(\frac{1}{x}\right)\,dx.
  5. Simplify Integral: Simplify the integral (12)x2(1x)dx\int(\frac{1}{2})x^{-2}(\frac{1}{x})dx. This simplifies to (12)x3dx(\frac{1}{2})\int x^{-3}dx.
  6. Integrate Simplified Integral: Integrate (12)x3dx(\frac{1}{2})\int x^{-3}\,dx. The integral of x3x^{-3} with respect to xx is 12×x2-\frac{1}{2} \times x^{-2}.
  7. Combine Integration Results: Combine the results from integration by parts. We have ln(5x)12x212(12x2)=12x2ln(5x)+14x2.\ln(5x)\cdot\frac{1}{2}x^{-2} - \frac{1}{2}\left(-\frac{1}{2} \cdot x^{-2}\right) = \frac{1}{2}x^{-2}\ln(5x) + \frac{1}{4}x^{-2}.
  8. Add Constant of Integration: Add the constant of integration CC to the result. The final answer is (12)x2ln(5x)+(14)x2+C(\frac{1}{2})x^{-2}\ln(5x) + (\frac{1}{4})x^{-2} + C.