Sine

Definition

The sine function is a trigonometric function that represents the ratio of the length of the opposite side to the length of the hypotenuse of a right triangle. It is one of the fundamental trigonometric functions used in various mathematical and scientific applications.

5 Must Know Facts For Your Next Test

1. The sine function is denoted by the symbol $\sin$, and it is one of the fundamental trigonometric functions.
2. The sine of an angle $\theta$ is the ratio of the length of the opposite side to the length of the hypotenuse of a right triangle with one angle equal to $\theta$.
3. The sine function is periodic, with a period of $2\pi$ radians or $360$ degrees.
4. The sine function has a range of $[-1, 1]$, meaning the values of the sine function will always be between -1 and 1.
5. The derivative of the sine function is the cosine function, $\frac{d}{dx}\sin(x) = \cos(x)$.

Review Questions

• Explain how the sine function is defined using the unit circle.
  • The sine function is defined on the unit circle, where the angle $\theta$ is measured counterclockwise from the positive x-axis. The sine of $\theta$ is the y-coordinate of the point on the unit circle where the angle $\theta$ intersects the circle. This means that the sine function represents the vertical (y) component of a point on the unit circle, which corresponds to the length of the opposite side of a right triangle with one angle equal to $\theta$.
• Describe the relationship between the sine function and the derivative of trigonometric functions.
  • The derivative of the sine function is the cosine function, $\frac{d}{dx}\sin(x) = \cos(x)$. This relationship is a fundamental property of trigonometric functions and is crucial in understanding the derivatives of trigonometric functions. The derivative of a trigonometric function can be expressed in terms of other trigonometric functions, allowing for the differentiation of expressions involving trigonometric functions.
• Analyze how the periodic nature of the sine function affects its applications in various mathematical and scientific contexts.
  • The periodic nature of the sine function, with a period of $2\pi$ radians or $360$ degrees, means that the function repeats itself at regular intervals. This property allows the sine function to be used to model and analyze periodic phenomena in various fields, such as wave motion, alternating current, and periodic functions in general. The periodic nature of the sine function also plays a crucial role in the study of Fourier series and the representation of periodic functions as a sum of sine and cosine terms.

Related terms

Trigonometric Functions:

Trigonometric functions are functions that relate the angles of a triangle to the lengths of its sides. The main trigonometric functions are sine, cosine, and tangent.

Unit Circle:

The unit circle is a circle with a radius of 1 unit, centered at the origin (0, 0) of the coordinate plane. It is used to define and visualize the trigonometric functions, including sine.

Angle Measure: Angle measure refers to the way of quantifying the size of an angle, typically in degrees or radians. The sine function is defined in terms of the angle measure.