Math Problem Statement

Solve the trigonometric equation for all values 0 < x < 10. sec(1/2 * x) + 1 = 0

Solution

The equation shown in the image is:

sec(12x)+1=0\sec\left(\frac{1}{2}x\right) + 1 = 0

We can solve this step by step.

Step 1: Isolate the secant function

Start by moving the 11 to the other side of the equation:

sec(12x)=1\sec\left(\frac{1}{2}x\right) = -1

Step 2: Recall the definition of secant

The secant function is the reciprocal of the cosine function, so:

sec(θ)=1cos(θ)\sec\left(\theta\right) = \frac{1}{\cos\left(\theta\right)}

This implies:

1cos(12x)=1\frac{1}{\cos\left(\frac{1}{2}x\right)} = -1

Step 3: Solve for cosine

To solve for the cosine, take the reciprocal of both sides:

cos(12x)=1\cos\left(\frac{1}{2}x\right) = -1

Step 4: Solve for xx

Now, we need to solve for xx where cos(12x)=1\cos\left(\frac{1}{2}x\right) = -1. The cosine function equals 1-1 at angles of the form:

12x=π+2kπforkZ\frac{1}{2}x = \pi + 2k\pi \quad \text{for} \quad k \in \mathbb{Z}

Solving for xx:

x=2π+4kπx = 2\pi + 4k\pi

So, x=2π(1+2k)x = 2\pi(1 + 2k), where kk is an integer.

Step 5: Apply the constraint 0<x<100 < x < 10

We now check which values of xx lie within the given interval 0<x<100 < x < 10. Let’s calculate the specific values of xx based on different values of kk:

  • For k=0k = 0: x=2π6.2832x = 2\pi \approx 6.2832
  • For k=1k = 1: x=6π18.8496x = 6\pi \approx 18.8496 (this is greater than 10, so it's out of range)

Thus, the only solution in the interval 0<x<100 < x < 10 is:

x=2π6.2832x = 2\pi \approx 6.2832

The solution is x=2πx = 2\pi.

Would you like more details, or have any questions?

Here are five related questions to explore:

  1. How would the solution change if the interval were different, such as 0<x<200 < x < 20?
  2. What is the period of the cosine function?
  3. How does the secant function behave near its asymptotes?
  4. Can you explain the behavior of the cosine function between 00 and 2π2\pi?
  5. How do transformations of trigonometric functions (like scaling) affect their graphs?

Tip: Always consider the interval given in trigonometric equations to limit your solutions appropriately.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Secant Function
Cosine Function

Formulas

sec(θ) = 1 / cos(θ)
cos(θ) = -1
x = 2π + 4kπ where k is an integer

Theorems

Secant-Cosine Relationship
Cosine Function at Specific Angles

Suitable Grade Level

Grades 10-12