The Angle Sum and Difference Identities

Oct 13, 2025 by windailys.com 51 views

Introduction

In mathematics, trigonometric functions play a crucial role in various mathematical operations and applications. The sine function, in particular, is a fundamental component of trigonometry, and its properties and identities are essential to understand and apply in different mathematical contexts. In this article, we will focus on the equation $\sin \left(\frac{\pi}{6}-x\right)$ and explore its equivalent forms.

The Angle Sum and Difference Identities

The angle sum and difference identities for sine are given by:

\sin (A+B) = \sin A \cos B + \cos A \sin B

\sin (A-B) = \sin A \cos B - \cos A \sin B

Using these identities, we can rewrite the given equation as:

\sin \left(\frac{\pi}{6}-x\right) = \sin \left(\frac{\pi}{6}\right) \cos (-x) - \cos \left(\frac{\pi}{6}\right) \sin (-x)

Properties of Sine and Cosine Functions

We know that:

\sin \left(\frac{\pi}{6}\right) = \frac{1}{2}

\cos \left(\frac{\pi}{6}\right) = \frac{\sqrt{3}}{2}

\cos (-x) = \cos x

\sin (-x) = -\sin x

Substituting these values into the equation, we get:

\sin \left(\frac{\pi}{6}-x\right) = \frac{1}{2} \cos x - \frac{\sqrt{3}}{2} (-\sin x)

Simplifying the Equation

Simplifying the equation further, we get:

\sin \left(\frac{\pi}{6}-x\right) = \frac{1}{2} \cos x + \frac{\sqrt{3}}{2} \sin x

Conclusion

In conclusion, the equation $\sin \left(\frac{\pi}{6}-x\right)$ is equal to $\frac{1}{2}(\cos x+\sqrt{3} \sin x)$ . This result can be obtained by applying the angle sum and difference identities for sine and using the properties of sine and cosine functions.

Comparison with Other Options

Let's compare the result with the other options:

A. $\frac{1}{2}(\cos x-\sqrt{3} \sin x)$

B. $\frac{1}{2}(\cos x+\sqrt{3} \sin x)$

C. $\frac{1}{2}(\sqrt{3} \cos x+\sin x)$

D. $\frac{1}{2}(\sqrt{3} \cos x-\sin x)$

Only option B matches the result we obtained.

Final Answer

The final answer is:

Q&A: Frequently Asked Questions

Q: What is the equation of sine?

A: The equation of sine is given by $\sin \left(\frac{\pi}{6}-x\right)$ .

Q: How do I simplify the equation of sine?

A: To simplify the equation of sine, you can apply the angle sum and difference identities for sine and use the properties of sine and cosine functions.

Q: What are the angle sum and difference identities for sine?

A: The angle sum and difference identities for sine are given by:

\sin (A+B) = \sin A \cos B + \cos A \sin B

\sin (A-B) = \sin A \cos B - \cos A \sin B

Q: How do I use the properties of sine and cosine functions?

A: You can use the properties of sine and cosine functions to simplify the equation of sine. For example, you can use the fact that $\sin \left(\frac{\pi}{6}\right) = \frac{1}{2}$ and $\cos \left(\frac{\pi}{6}\right) = \frac{\sqrt{3}}{2}$ .

Q: What is the final answer to the equation of sine?

A: The final answer to the equation of sine is $\frac{1}{2}(\cos x+\sqrt{3} \sin x)$ .

Q: How do I compare the result with other options?

A: To compare the result with other options, you can simply substitute the values of the options into the equation and see which one matches the result.

Q: What are the other options for the equation of sine?

A: The other options for the equation of sine are:

A. $\frac{1}{2}(\cos x-\sqrt{3} \sin x)$

B. $\frac{1}{2}(\cos x+\sqrt{3} \sin x)$

C. $\frac{1}{2}(\sqrt{3} \cos x+\sin x)$

D. $\frac{1}{2}(\sqrt{3} \cos x-\sin x)$

Q: Which option matches the result?

A: Only option B matches the result.

Q: What is the significance of the equation of sine?

A: The equation of sine is a fundamental component of trigonometry and has many applications in mathematics and physics.

Q: How do I apply the equation of sine in real-world problems?

A: You can apply the equation of sine in real-world problems such as calculating the height of a building, the distance between two points, or the angle of elevation of a object.

Q: What are some common applications of the equation of sine?

A: Some common applications of the equation of sine include:

Calculating the height of a building
Calculating the distance between two points
Calculating the angle of elevation of an object
Calculating the area of a triangle
Calculating the volume of a pyramid

Q: How do I use the equation of sine in calculus?

A: You can use the equation of sine in calculus to calculate the derivative and integral of trigonometric functions.

Q: What are some common calculus applications of the equation of sine?

A: Some common calculus applications of the equation of sine include:

Calculating the derivative of trigonometric functions
Calculating the integral of trigonometric functions
Calculating the area under a curve
Calculating the volume of a solid
Calculating the surface area of a solid