Math Problem Statement

Solve for x in the equation: cos²(x)/7 + sin²(x)/7 = 8

Solution

The given equation from the image is:

cos2(x)7+sin2(x)7=8\frac{\cos^2(x)}{7} + \frac{\sin^2(x)}{7} = 8

We can factor out 17\frac{1}{7}:

17(cos2(x)+sin2(x))=8\frac{1}{7}(\cos^2(x) + \sin^2(x)) = 8

Now, we use the Pythagorean identity cos2(x)+sin2(x)=1\cos^2(x) + \sin^2(x) = 1:

17(1)=8\frac{1}{7}(1) = 8

Simplifying:

17=8\frac{1}{7} = 8

This equation is not true, meaning no real solution exists for xx based on this equation, since 17\frac{1}{7} cannot equal 8.

Would you like further explanation on this? Here are five related questions to think about:

  1. What is the Pythagorean identity for sine and cosine?
  2. How can you solve other trigonometric equations with different identities?
  3. What if the equation had different coefficients—would it have a solution?
  4. How are trigonometric identities useful in physics and engineering?
  5. What happens when solving complex trigonometric equations in calculus?

Tip: Always double-check the identities you use, as they simplify many trigonometric expressions.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Pythagorean Identity
Equations

Formulas

cos²(x) + sin²(x) = 1
Basic algebraic manipulation

Theorems

Pythagorean Identity

Suitable Grade Level

Grades 10-12