Math Problem Statement

Evaluate the integral \(\int \left( \frac{1}{\sqrt{(x - 1)(x - 5)}} + \frac{2x - 3}{x^2 - 4x + 13} \right) dx\).

Solution

This integral involves a rational function and a square root in the denominator. The given expression is:

(1(x1)(x5)+2x3x24x+13)dx\int \left( \frac{1}{\sqrt{(x - 1)(x - 5)}} + \frac{2x - 3}{x^2 - 4x + 13} \right) dx

Steps to Solve:

  1. Separate the integral: 1(x1)(x5)dx+2x3x24x+13dx\int \frac{1}{\sqrt{(x - 1)(x - 5)}} dx + \int \frac{2x - 3}{x^2 - 4x + 13} dx

  2. Simplify the first term:

    • The denominator (x1)(x5)\sqrt{(x - 1)(x - 5)} suggests a substitution like x=3+2cosθx = 3 + 2\cos\theta, since it represents a square root of a quadratic in factored form.
    • Rewrite and substitute accordingly to simplify.
  3. Simplify the second term:

    • The denominator x24x+13x^2 - 4x + 13 is a quadratic. Complete the square: x24x+13=(x2)2+9x^2 - 4x + 13 = (x - 2)^2 + 9
    • Use the substitution u=x2u = x - 2, so the integral becomes: 2uu2+9du\int \frac{2u}{u^2 + 9} du
    • Solve using standard forms for arctangent integrals.

Let me calculate and simplify these integrals step by step. One moment! sympy as sp

Define the variables

x = sp.symbols('x')

Define the two terms of the integral

term1 = 1 / sp.sqrt((x - 1) * (x - 5)) term2 = (2x - 3) / (x**2 - 4x + 13)

Complete the square for the second term denominator

denom_term2 = x**2 - 4*x + 13 completed_square = sp.simplify(denom_term2)

Integrate both terms

integral_term1 = sp.integrate(term1, x) integral_term2 = sp.integrate(term2, x)

integral_term1, integral_term2The solution involves the following steps for the two terms of the integral:

  1. First term: The integral remains unevaluated in its current form due to the complexity: 1(x1)(x5)dx\int \frac{1}{\sqrt{(x - 1)(x - 5)}} dx This may require a substitution like x=3+2cosθx = 3 + 2\cos\theta, which simplifies the square root. Additional steps would be needed for explicit evaluation.

  2. Second term: After completing the square for the denominator x24x+13=(x2)2+9x^2 - 4x + 13 = (x - 2)^2 + 9, the integral simplifies to: 2x3x24x+13dx=ln(x24x+13)+13arctan(x23)+C\int \frac{2x - 3}{x^2 - 4x + 13} dx = \ln(x^2 - 4x + 13) + \frac{1}{3} \arctan\left(\frac{x - 2}{3}\right) + C

Would you like me to explicitly evaluate the first term further or explain the substitution process? Let me know!


Relative Questions:

  1. How do substitutions simplify square roots in integrals?
  2. Can trigonometric substitutions always be applied to simplify expressions involving (xa)(xb)\sqrt{(x-a)(x-b)}?
  3. What role does completing the square play in evaluating integrals?
  4. How does the arctan\arctan term appear in integrals involving quadratic denominators?
  5. Would you like a graphical explanation of how substitutions transform the integral?

Tip: Always try completing the square for quadratic expressions to simplify integration involving trigonometric or logarithmic terms.

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Math Problem Analysis

Mathematical Concepts

Integration of rational functions
Square root simplification
Trigonometric substitution
Completing the square
Arctangent integration

Formulas

\(\int \frac{1}{\sqrt{(x-a)(x-b)}} dx\) using trigonometric substitution
\(\int \frac{1}{x^2 + a^2} dx = \frac{1}{a}\arctan\left(\frac{x}{a}\right) + C\)

Theorems

Method of completing the square
Substitution for rational functions with square roots

Suitable Grade Level

Undergraduate mathematics (calculus)