Math Problem Statement

cos(2π - α) * (tg(3π/2 - α))^2 * tg(2π + α) * (ctg(π/2 + α))^2;

Solution

The expression in the image is:

cos(2πα)(tan(3π2α))2tan(2π+α)(cot(π2+α))2\cos(2\pi - \alpha) \cdot \left(\tan\left(\frac{3\pi}{2} - \alpha\right)\right)^2 \cdot \tan(2\pi + \alpha) \cdot \left(\cot\left(\frac{\pi}{2} + \alpha\right)\right)^2

Let's simplify it step by step:

  1. Cosine of 2πα2\pi - \alpha: cos(2πα)=cos(α)\cos(2\pi - \alpha) = \cos(\alpha) because cosine is an even function.

  2. Tangent of 3π2α\frac{3\pi}{2} - \alpha: tan(3π2α)=cot(α)\tan\left(\frac{3\pi}{2} - \alpha\right) = -\cot(\alpha) This follows from the tangent function's periodicity and transformations.

  3. Tangent of 2π+α2\pi + \alpha: tan(2π+α)=tan(α)\tan(2\pi + \alpha) = \tan(\alpha) since the tangent function has a period of π\pi.

  4. Cotangent of π2+α\frac{\pi}{2} + \alpha: cot(π2+α)=tan(α)\cot\left(\frac{\pi}{2} + \alpha\right) = -\tan(\alpha) because cot(π2+x)=tan(x)\cot(\frac{\pi}{2} + x) = -\tan(x).

Substituting back into the original expression:

cos(α)(cot(α))2tan(α)(tan(α))2\cos(\alpha) \cdot \left(-\cot(\alpha)\right)^2 \cdot \tan(\alpha) \cdot \left(-\tan(\alpha)\right)^2

This simplifies to:

cos(α)cot2(α)tan(α)tan2(α)\cos(\alpha) \cdot \cot^2(\alpha) \cdot \tan(\alpha) \cdot \tan^2(\alpha)

Now, use the identity cot(α)=1tan(α)\cot(\alpha) = \frac{1}{\tan(\alpha)}:

cos(α)(1tan(α))2tan(α)tan2(α)\cos(\alpha) \cdot \left(\frac{1}{\tan(\alpha)}\right)^2 \cdot \tan(\alpha) \cdot \tan^2(\alpha)

Simplifying further:

cos(α)1tan2(α)tan(α)tan2(α)\cos(\alpha) \cdot \frac{1}{\tan^2(\alpha)} \cdot \tan(\alpha) \cdot \tan^2(\alpha)

Cancel tan2(α)\tan^2(\alpha) with the 1tan2(α)\frac{1}{\tan^2(\alpha)}:

cos(α)\cos(\alpha)

Final simplified result:

The entire expression simplifies to cos(α)\cos(\alpha).


Would you like more details or have any questions?

Here are some related questions you can explore:

  1. What are the key properties of trigonometric functions under transformations?
  2. How does the periodicity of trigonometric functions affect their transformations?
  3. Can cotangent and tangent identities help simplify other complex trigonometric expressions?
  4. What is the relationship between even and odd functions, like cosine and sine?
  5. How do you determine whether an expression can be simplified further?

Tip: When simplifying trigonometric expressions, always look for basic identities and function periodicity to reduce complexity.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Function Transformations
Even and Odd Functions
Trigonometric Identities

Formulas

cos(2π - α) = cos(α)
tan(3π/2 - α) = -cot(α)
tan(2π + α) = tan(α)
cot(π/2 + α) = -tan(α)
cot(α) = 1/tan(α)

Theorems

Periodicity of Trigonometric Functions
Even-Odd Function Properties
Basic Trigonometric Identities

Suitable Grade Level

Grades 10-12