Math Problem Statement

Factor and simplify the expression 3cos^2(x) + cos(x) - 4.

Solution

The equation given in the image is:

3cos2(x)+cos(x)43\cos^2(x) + \cos(x) - 4

Steps to Factor and Simplify:

  1. Substitute u=cos(x)u = \cos(x): This simplifies the equation into a quadratic form: 3u2+u43u^2 + u - 4

  2. Factor the quadratic equation: We need to find factors of 3u2+u43u^2 + u - 4. We look for two numbers that multiply to 3×4=123 \times -4 = -12 and add to 11. The pair 44 and 3-3 works.

    Now split the middle term: 3u2+4u3u43u^2 + 4u - 3u - 4 Group terms: (3u23u)+(4u4)(3u^2 - 3u) + (4u - 4) Factor each group: 3u(u1)+4(u1)3u(u - 1) + 4(u - 1) Factor out the common binomial (u1)(u - 1): (3u+4)(u1)(3u + 4)(u - 1)

  3. Substitute back u=cos(x)u = \cos(x): (3cos(x)+4)(cos(x)1)(3\cos(x) + 4)(\cos(x) - 1)

Thus, the factored form of the expression is: (3cos(x)+4)(cos(x)1)(3\cos(x) + 4)(\cos(x) - 1)

Final Simplified Answer:

(3cos(x)+4)(cos(x)1)(3\cos(x) + 4)(\cos(x) - 1)

Would you like more details on any part of the process or have any questions?

Here are 5 related questions to expand your understanding:

  1. How do you solve a quadratic equation using the factoring method?
  2. What are some other trigonometric identities that can be factored like this?
  3. How can this factoring method be applied to solve for xx in trigonometric equations?
  4. What are alternative methods to solving trigonometric quadratics besides factoring?
  5. How does the substitution method simplify complex trigonometric expressions?

Tip: When dealing with quadratic trigonometric expressions, always check if substitution can simplify the equation into a solvable form!

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Quadratic Equations
Factoring

Formulas

Quadratic formula ax^2 + bx + c = 0
Trigonometric identities

Theorems

Factoring quadratic equations

Suitable Grade Level

Grades 10-12