Math Problem Statement

\int \frac{1}{2x^2 + 4x + 5} \, dx

Solution

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Just a moment while I analyze the image.The uploaded image contains an integral problem that can be expressed as:

12x2+4x+5dx\int \frac{1}{2x^2 + 4x + 5} \, dx

To solve this, we'll first complete the square for the quadratic in the denominator.

Step 1: Completing the Square

We have: 2x2+4x+52x^2 + 4x + 5 Factor out the 2 from the first two terms: 2(x2+2x)+52(x^2 + 2x) + 5 Now, complete the square inside the parentheses: x2+2x=(x+1)21x^2 + 2x = (x+1)^2 - 1 So we get: 2((x+1)21)+5=2(x+1)2+32((x+1)^2 - 1) + 5 = 2(x+1)^2 + 3

Step 2: Substitute and Solve

Now, the integral becomes: 12(x+1)2+3dx\int \frac{1}{2(x+1)^2 + 3} \, dx We can factor out the constant 2 from the denominator: 121(x+1)2+32dx\frac{1}{2} \int \frac{1}{(x+1)^2 + \frac{3}{2}} \, dx This is now in the form of a standard arctangent integral: 1u2+a2du=1aarctan(ua)\int \frac{1}{u^2 + a^2} \, du = \frac{1}{a} \arctan\left( \frac{u}{a} \right) Here, u=x+1u = x+1 and a=32a = \sqrt{\frac{3}{2}}. Applying this, we get: 132arctan(x+132)\frac{1}{\sqrt{\frac{3}{2}}} \arctan\left( \frac{x+1}{\sqrt{\frac{3}{2}}} \right) Simplifying the constant: 132=23\frac{1}{\sqrt{\frac{3}{2}}} = \frac{\sqrt{2}}{\sqrt{3}} Thus, the final solution is: 23arctan(x+132)+C\frac{\sqrt{2}}{\sqrt{3}} \arctan\left( \frac{x+1}{\sqrt{\frac{3}{2}}} \right) + C

Would you like further details on this solution or have any questions?

Here are 5 related questions to explore:

  1. How is completing the square used to simplify integrals?
  2. What is the formula for the integral of 1x2+a2\frac{1}{x^2 + a^2}?
  3. How do you handle integrals involving quadratic expressions in the denominator?
  4. What role does substitution play in simplifying complex integrals?
  5. Can you generalize this method for other quadratic functions?

Tip: Completing the square is a powerful technique to simplify integrals involving quadratics!

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Math Problem Analysis

Mathematical Concepts

Integration
Completing the Square
Trigonometric Substitution

Formulas

Completing the square for ax^2 + bx + c = a(x + b/(2a))^2 - (b^2 - 4ac)/(4a)
Standard integral: \int \frac{1}{u^2 + a^2} \, du = \frac{1}{a} \arctan\left( \frac{u}{a} \right)

Theorems

Arctangent Integral Formula

Suitable Grade Level

Undergraduate Calculus or Advanced High School Calculus