Math Problem Statement

Реши задание

Реши задание

Solution

To solve the problem, I will analyze the provided image step by step. The question appears to involve simplifying and solving an integral, which includes a square root in the denominator and requires substitution to proceed. Let's focus on translating the task and solving it.


Transcription of the task from the image:

We are asked to evaluate the following integral:

3x1x28x+32dx\int \frac{3x - 1}{\sqrt{x^2 - 8x + 32}} \, dx

Steps provided in the example:

  1. Complete the square in the denominator: x28x+32=(x4)2+16x^2 - 8x + 32 = (x - 4)^2 + 16 So, the integral becomes: 3x1(x4)2+16dx\int \frac{3x - 1}{\sqrt{(x - 4)^2 + 16}} \, dx

  2. Substitute the variable: Let t=x4t = x - 4, so x=t+4x = t + 4 and dx=dtdx = dt.

    Substituting these values into the integral gives: 3(t+4)1t2+16dt=3t+11t2+16dt\int \frac{3(t + 4) - 1}{\sqrt{t^2 + 16}} \, dt = \int \frac{3t + 11}{\sqrt{t^2 + 16}} \, dt

  3. Split the integral: 3t+11t2+16dt=3tt2+16dt+11t2+16dt\int \frac{3t + 11}{\sqrt{t^2 + 16}} \, dt = \int \frac{3t}{\sqrt{t^2 + 16}} \, dt + \int \frac{11}{\sqrt{t^2 + 16}} \, dt

    Each term is now integrated separately.

  4. Integrate the first term: For 3tt2+16dt\int \frac{3t}{\sqrt{t^2 + 16}} \, dt, use substitution u=t2+16u = t^2 + 16, so du=2tdtdu = 2t \, dt.

    The integral becomes: 3tt2+16dt=3tt2+16dt=3t2+16\int \frac{3t}{\sqrt{t^2 + 16}} \, dt = 3 \int \frac{t}{\sqrt{t^2 + 16}} \, dt = 3 \cdot \sqrt{t^2 + 16}

  5. Integrate the second term: For 11t2+16dt\int \frac{11}{\sqrt{t^2 + 16}} \, dt, recognize this as a standard integral of the form: 1t2+a2dt=lnt+t2+a2\int \frac{1}{\sqrt{t^2 + a^2}} \, dt = \ln|t + \sqrt{t^2 + a^2}| Here, a=4a = 4, so: 11t2+16dt=11lnt+t2+16\int \frac{11}{\sqrt{t^2 + 16}} \, dt = 11 \ln|t + \sqrt{t^2 + 16}|

  6. Combine the results: Adding the two parts together, we have: 3t+11t2+16dt=3t2+16+11lnt+t2+16\int \frac{3t + 11}{\sqrt{t^2 + 16}} \, dt = 3\sqrt{t^2 + 16} + 11\ln|t + \sqrt{t^2 + 16}|

  7. Return to the original variable xx: Recall that t=x4t = x - 4, so t2+16=(x4)2+16t^2 + 16 = (x - 4)^2 + 16. Substituting back: 3x1x28x+32dx=3(x4)2+16+11lnx4+(x4)2+16+C\int \frac{3x - 1}{\sqrt{x^2 - 8x + 32}} \, dx = 3\sqrt{(x - 4)^2 + 16} + 11\ln|x - 4 + \sqrt{(x - 4)^2 + 16}| + C


Final Answer:

3x1x28x+32dx=3(x4)2+16+11lnx4+(x4)2+16+C\int \frac{3x - 1}{\sqrt{x^2 - 8x + 32}} \, dx = 3\sqrt{(x - 4)^2 + 16} + 11\ln|x - 4 + \sqrt{(x - 4)^2 + 16}| + C


Would you like further clarification on any steps?

Related Questions:

  1. How do you complete the square for quadratic expressions?
  2. What are standard integrals involving square roots, such as t2+a2\sqrt{t^2 + a^2}?
  3. Why is substitution useful in solving integrals like these?
  4. Can we solve this integral using another method, such as trigonometric substitution?
  5. How do you determine the constant of integration CC for definite integrals?

Tip:

When solving integrals involving quadratic expressions, completing the square is often the first critical step to simplify the denominator!

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Math Problem Analysis

Mathematical Concepts

Integration
Substitution Method
Completing the Square

Formulas

Integration of 1/sqrt(t^2 + a^2): ∫(1/√(t^2 + a^2)) dt = ln|t + √(t^2 + a^2)| + C
Completing the square: ax^2 + bx + c → (x - h)^2 + k where h = -b/2a and k = c - (b^2/4a)

Theorems

Standard Integral Theorem for sqrt(t^2 + a^2)
Substitution Method in Integration

Suitable Grade Level

University Level (Calculus)