Solve The Trigonometric Equation For All Values $0 \leq X \ \textless \ 2\pi$.$3 \tan X = -\sqrt{3}$

by ADMIN 103 views

Introduction

Trigonometric equations are a fundamental concept in mathematics, and solving them is a crucial skill for students and professionals alike. In this article, we will focus on solving the trigonometric equation 3tanx=33 \tan x = -\sqrt{3} for all values 0x \textless 2π0 \leq x \ \textless \ 2\pi. We will break down the solution into manageable steps, using a combination of trigonometric identities and algebraic manipulations.

Understanding the Equation

The given equation is 3tanx=33 \tan x = -\sqrt{3}. To solve this equation, we need to isolate the variable xx. The first step is to divide both sides of the equation by 3, which gives us tanx=33\tan x = -\frac{\sqrt{3}}{3}.

Using Trigonometric Identities

We can use the trigonometric identity tanx=sinxcosx\tan x = \frac{\sin x}{\cos x} to rewrite the equation as sinxcosx=33\frac{\sin x}{\cos x} = -\frac{\sqrt{3}}{3}. This identity allows us to express the tangent function in terms of the sine and cosine functions.

Simplifying the Equation

We can simplify the equation by multiplying both sides by cosx\cos x, which gives us sinx=33cosx\sin x = -\frac{\sqrt{3}}{3} \cos x. This equation is still in terms of the sine and cosine functions, but it is now in a more manageable form.

Using the Pythagorean Identity

We can use the Pythagorean identity sin2x+cos2x=1\sin^2 x + \cos^2 x = 1 to rewrite the equation as sin2x+cos2x=(33cosx)2\sin^2 x + \cos^2 x = \left(-\frac{\sqrt{3}}{3} \cos x\right)^2. This identity allows us to express the sum of the squares of the sine and cosine functions in terms of a single variable.

Solving for x

We can simplify the equation by expanding the right-hand side, which gives us sin2x+cos2x=13cos2x\sin^2 x + \cos^2 x = \frac{1}{3} \cos^2 x. We can then subtract cos2x\cos^2 x from both sides, which gives us sin2x=23cos2x\sin^2 x = -\frac{2}{3} \cos^2 x.

Using the Quadratic Formula

We can use the quadratic formula to solve for cosx\cos x. The quadratic formula is given by x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}. In this case, we have a=23a = -\frac{2}{3}, b=0b = 0, and c=1c = 1. Plugging these values into the quadratic formula, we get cosx=0±04(23)(1)2(23)\cos x = \frac{0 \pm \sqrt{0 - 4\left(-\frac{2}{3}\right)\left(1\right)}}{2\left(-\frac{2}{3}\right)}.

Simplifying the Quadratic Formula

We can simplify the quadratic formula by evaluating the expression under the square root. This gives us cosx=0±8343\cos x = \frac{0 \pm \sqrt{\frac{8}{3}}}{-\frac{4}{3}}.

Solving for x

We can simplify the expression by multiplying both sides by 34-\frac{3}{4}, which gives us cosx=22\cos x = \mp \frac{\sqrt{2}}{2}. We can then use the inverse cosine function to solve for xx. The inverse cosine function is given by x=cos1(22)x = \cos^{-1} \left(\mp \frac{\sqrt{2}}{2}\right).

Finding the Solutions

We can use a calculator or a trigonometric table to find the values of xx that satisfy the equation. The solutions are given by x=cos1(22)x = \cos^{-1} \left(-\frac{\sqrt{2}}{2}\right) and x=π+cos1(22)x = \pi + \cos^{-1} \left(-\frac{\sqrt{2}}{2}\right).

Conclusion

In this article, we solved the trigonometric equation 3tanx=33 \tan x = -\sqrt{3} for all values 0x \textless 2π0 \leq x \ \textless \ 2\pi. We used a combination of trigonometric identities and algebraic manipulations to isolate the variable xx. The solutions are given by x=cos1(22)x = \cos^{-1} \left(-\frac{\sqrt{2}}{2}\right) and x=π+cos1(22)x = \pi + \cos^{-1} \left(-\frac{\sqrt{2}}{2}\right). We hope that this article has provided a clear and concise explanation of how to solve trigonometric equations.

Additional Resources

For more information on trigonometric equations, we recommend the following resources:

Final Thoughts

Q: What is a trigonometric equation?

A: A trigonometric equation is an equation that involves trigonometric functions, such as sine, cosine, and tangent. These equations can be used to model real-world problems, such as the motion of objects or the behavior of electrical circuits.

Q: How do I solve a trigonometric equation?

A: To solve a trigonometric equation, you need to isolate the variable, which is usually represented by x. You can use a combination of trigonometric identities and algebraic manipulations to solve the equation.

Q: What are some common trigonometric identities?

A: Some common trigonometric identities include:

  • sin2x+cos2x=1\sin^2 x + \cos^2 x = 1
  • tanx=sinxcosx\tan x = \frac{\sin x}{\cos x}
  • cotx=cosxsinx\cot x = \frac{\cos x}{\sin x}
  • secx=1cosx\sec x = \frac{1}{\cos x}
  • cscx=1sinx\csc x = \frac{1}{\sin x}

Q: How do I use the Pythagorean identity to solve a trigonometric equation?

A: The Pythagorean identity is sin2x+cos2x=1\sin^2 x + \cos^2 x = 1. You can use this identity to rewrite the equation in terms of a single variable, such as sinx\sin x or cosx\cos x.

Q: What is the quadratic formula?

A: The quadratic formula is a mathematical formula that is used to solve quadratic equations. It is given by x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}.

Q: How do I use the quadratic formula to solve a trigonometric equation?

A: To use the quadratic formula to solve a trigonometric equation, you need to rewrite the equation in the form of a quadratic equation. You can then use the quadratic formula to solve for the variable.

Q: What are some common mistakes to avoid when solving trigonometric equations?

A: Some common mistakes to avoid when solving trigonometric equations include:

  • Not using the correct trigonometric identity
  • Not isolating the variable
  • Not checking the solutions
  • Not using the correct method to solve the equation

Q: How do I check my solutions to a trigonometric equation?

A: To check your solutions to a trigonometric equation, you need to plug the solutions back into the original equation. If the solutions satisfy the equation, then they are valid solutions.

Q: What are some real-world applications of trigonometric equations?

A: Some real-world applications of trigonometric equations include:

  • Modeling the motion of objects
  • Analyzing the behavior of electrical circuits
  • Solving problems in physics and engineering
  • Modeling population growth and decay

Q: How do I practice solving trigonometric equations?

A: To practice solving trigonometric equations, you can try the following:

  • Work on practice problems
  • Use online resources, such as Khan Academy or MIT OpenCourseWare
  • Join a study group or find a study partner
  • Take online courses or attend workshops

Conclusion

Solving trigonometric equations is a crucial skill for students and professionals alike. In this article, we provided a step-by-step guide on how to solve trigonometric equations, as well as some frequently asked questions and answers. We hope that this article has provided a clear and concise explanation of how to solve trigonometric equations.