Math Problem Statement

now do 7sin(2x)-1 = 3sin(2x)+2 for 0 < x < 2pie

Solution

Let's solve the equation:

7sin(2x)1=3sin(2x)+27\sin(2x) - 1 = 3\sin(2x) + 2

Step 1: Move all terms involving sin(2x)\sin(2x) to one side.

Subtract 3sin(2x)3\sin(2x) from both sides:

7sin(2x)3sin(2x)1=27\sin(2x) - 3\sin(2x) - 1 = 2

This simplifies to:

4sin(2x)1=24\sin(2x) - 1 = 2

Step 2: Isolate sin(2x)\sin(2x).

Add 1 to both sides:

4sin(2x)=34\sin(2x) = 3

Now, divide both sides by 4:

sin(2x)=34\sin(2x) = \frac{3}{4}

Step 3: Solve for xx.

Take the inverse sine of both sides:

2x=sin1(34)2x = \sin^{-1}\left(\frac{3}{4}\right)

Using a calculator, sin1(34)0.848\sin^{-1}\left(\frac{3}{4}\right) \approx 0.848 radians.

So,

2x=0.848or2x=π0.848=2.293(since sine is positive in both the first and second quadrants).2x = 0.848 \quad \text{or} \quad 2x = \pi - 0.848 = 2.293 \quad \text{(since sine is positive in both the first and second quadrants)}.

Step 4: Solve for xx.

Divide both values by 2:

x=0.84820.424orx=2.29321.146x = \frac{0.848}{2} \approx 0.424 \quad \text{or} \quad x = \frac{2.293}{2} \approx 1.146

Step 5: Find other solutions.

Since sine has a period of 2π2\pi, we can find additional solutions by adding multiples of π\pi to xx.

So the general solutions are:

x=0.424+nπorx=1.146+nπx = 0.424 + n\pi \quad \text{or} \quad x = 1.146 + n\pi

Where nn is any integer.

Step 6: Determine the solutions in the interval 0<x<2π0 < x < 2\pi.

For x=0.424+nπx = 0.424 + n\pi:

  • For n=0n = 0, x0.424x \approx 0.424
  • For n=1n = 1, x0.424+π3.566x \approx 0.424 + \pi \approx 3.566

For x=1.146+nπx = 1.146 + n\pi:

  • For n=0n = 0, x1.146x \approx 1.146
  • For n=1n = 1, x1.146+π4.287x \approx 1.146 + \pi \approx 4.287

Thus, the solutions in the interval 0<x<2π0 < x < 2\pi are approximately:

x0.424,1.146,3.566,4.287x \approx 0.424, \, 1.146, \, 3.566, \, 4.287

Final Answer:

The solutions are x0.424,1.146,3.566,4.287x \approx 0.424, 1.146, 3.566, 4.287 in the interval 0<x<2π0 < x < 2\pi.


Would you like further details on any part of the process? Or do you have any follow-up questions?

Related questions:

  1. How does the period of the sine function influence the number of solutions?
  2. How can we check if these solutions are valid by substituting them back into the original equation?
  3. How do you solve trigonometric equations involving multiple angles (e.g., sin(3x)\sin(3x))?
  4. What are the general methods for solving equations with trigonometric identities?
  5. How can we use the unit circle to visualize solutions to trigonometric equations?

Tip:

When solving trigonometric equations, always remember to check for all possible solutions within the given interval by considering the periodic nature of trigonometric functions.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Sine Function
Equation Solving

Formulas

sin^{-1}(x)
sin(2x) = 3/4

Theorems

Inverse Sine Theorem
Periodicity of Sine Function

Suitable Grade Level

Grades 11-12