Math Problem Statement

∫ dx / [sin(x)(1 + 2 cos(x))]

Solution

The given expression in the image is an integral:

dxsin(x)(1+2cos(x))\int \frac{dx}{\sin(x)(1 + 2 \cos(x))}

This is an integral of a rational function involving sine and cosine. A common approach to solve integrals like this is to use substitution or trigonometric identities to simplify the expression.

Let's try to solve it:

  1. Substitute u=cos(x)u = \cos(x):

    • Then, du=sin(x)dxdu = -\sin(x) dx, so the integral becomes:

    du(1+2u)\int \frac{-du}{(1 + 2u)}

  2. Simplify the integral:

    du1+2u-\int \frac{du}{1 + 2u}

  3. Solve the integral: This is a basic logarithmic integral. The solution is:

    12ln1+2u+C-\frac{1}{2} \ln |1 + 2u| + C

  4. Substitute back u=cos(x)u = \cos(x):

    12ln1+2cos(x)+C-\frac{1}{2} \ln |1 + 2\cos(x)| + C

Thus, the solution to the integral is:

12ln1+2cos(x)+C-\frac{1}{2} \ln |1 + 2 \cos(x)| + C


Would you like a more detailed explanation of any step or further clarification?

Here are 5 related questions for further practice:

  1. How do you solve integrals involving trigonometric functions like sin(x)\sin(x) and cos(x)\cos(x)?
  2. Can you solve the integral dx1+cos(x)\int \frac{dx}{1 + \cos(x)}?
  3. What are common substitutions for integrals involving trigonometric functions?
  4. How would you approach the integral dxsin(x)(1cos(x))\int \frac{dx}{\sin(x) (1 - \cos(x))}?
  5. What is the method to integrate rational functions of sine and cosine?

Tip: Substituting trigonometric functions can often simplify complex-looking integrals!

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Math Problem Analysis

Mathematical Concepts

Integral Calculus
Trigonometric Substitution

Formulas

∫ dx / [sin(x)(1 + 2 cos(x))]
Substitution u = cos(x), du = -sin(x) dx
Logarithmic integration

Theorems

Substitution Method
Logarithmic Integration

Suitable Grade Level

Undergraduate Calculus