Math Problem Statement

Solve the trigonometric equation for all values 0 ≤ x < 2π: √2 sec x + 2 = 0.

Solution

To solve the trigonometric equation

2secx+2=0\sqrt{2} \sec x + 2 = 0

for all values 0x<2π0 \leq x < 2\pi, we proceed as follows:

Solution Steps:

  1. Isolate secx\sec x: 2secx=2\sqrt{2} \sec x = -2 secx=22\sec x = -\frac{2}{\sqrt{2}} Simplifying: secx=2\sec x = -\sqrt{2}

  2. Recall that secx=1cosx\sec x = \frac{1}{\cos x}. Thus: 1cosx=2\frac{1}{\cos x} = -\sqrt{2} Therefore: cosx=12=22\cos x = -\frac{1}{\sqrt{2}} = -\frac{\sqrt{2}}{2}

  3. Identify the angles where cosx=22\cos x = -\frac{\sqrt{2}}{2}. This occurs at: x=3π4andx=5π4x = \frac{3\pi}{4} \quad \text{and} \quad x = \frac{5\pi}{4} within the interval 0x<2π0 \leq x < 2\pi.

Final Answer:

The solutions to the equation in the interval 0x<2π0 \leq x < 2\pi are: x=3π4,x=5π4x = \frac{3\pi}{4}, \quad x = \frac{5\pi}{4}

Would you like more detailed explanations on any steps or have any questions? Here are some related questions to further explore:

  1. What are the properties of secant and how does it relate to cosine?
  2. How do we convert between secant values and cosine values?
  3. What are the trigonometric values of other common angles such as π/4\pi/4 and 3π/23\pi/2?
  4. What is the significance of the interval 0x<2π0 \leq x < 2\pi in trigonometric problems?
  5. How would this problem change if secx\sec x was positive?

Tip: Remember that secx\sec x is undefined when cosx=0\cos x = 0, so watch out for domain restrictions in similar problems.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Trigonometric Equations
Secant and Cosine Relationships

Formulas

sec x = 1 / cos x
cos x = -√2 / 2

Theorems

Basic Trigonometric Identities

Suitable Grade Level

Grade 11-12