# Sin pi/6 – A Comprehensive Guide With Examples

In the fascinating world of trigonometry, sin (pi/6) or sin(π/6) is one such mathematical entity that often mystifies yet intrigues learners and scholars alike. We embark on exploring the fundamentals of the trigonometric function sin(π/6), a labyrinth of numbers, equations, and functions that underpin our understanding of countless natural and artificial phenomena.

Among the numerous angles at which the sine function is evaluated, one particular angle, π/6 radians (or equivalently, 30 degrees), holds considerable importance due to its straightforward computation and numerous applications across diverse fields.

This article delves into the nuances of the sine function, the significance of the angle π/6, the interpretation of sin(π/6), and its broader implications in mathematics and beyond.

## Definition of sin(pi/6)

Sin(π/6) is equal to 0.5 in value. The sine function (sin) of trigonometry is used to link the lengths of the hypotenuse and the side facing the angle in a right triangle. Sin(π/6) is the ratio of the length of the side opposite the angle to the length of the hypotenuse, in this case, the shorter side of an equilateral triangle, when the angle π/6, which is equal to 30 degrees, is used as the angle.

Figure-1.

The values of sin(π/6) are also known as “sine of 30 degrees” and “sine of π/6 radians,” among other names. The length of the side opposite the 30-degree angle is equal to half that of the hypotenuse since sin(π/6) in this case equals 0.5.

Numerous mathematical and scientific applications make use of the sin(π/6) value. It is utilized for calculations involving angles, distances, and proportions in disciplines including trigonometry, geometry, physics, and engineering. It is possible to accurately represent and analyze a variety of natural occurrences and physical attributes by knowing the sine function and its values.

## Mathematical Properties of sin(pi/6)

The mathematical function sin(π/6) has several interesting properties and features, owing to its position within the broader structure of trigonometric functions. Let’s delve into these:

### Value

The fundamental property of sin(π/6) is its value, which is 1/2. This comes from the geometry of a 30-60-90 triangle, in which the ratio of the side opposite the 30-degree angle (π/6 rad) to the hypotenuse is 1/2.

### Periodicity

The sine function is periodic with a period of . That means if you add any integer multiple of 2π to π/6, the sine of the resulting angle is the same as sin(π/6). Mathematically, this can be written as sin(π/6 + 2nπ) = sin(π/6), where n is any integer.

### Symmetry

The sine function is symmetric about the origin in the coordinate plane, which implies that sin(-θ) = -sin(θ). Therefore, sin(-π/6) = -sin(π/6) = -1/2.

### Co-function Identity

Sin(π/6) is also related to its co-function, the cosine, through the relationship sin(π/2 – θ) = cos(θ). Therefore, sin(π/2 – π/6) = sin(π/3) = cos(π/6). This is an example of a co-function identity.

### Sum and Difference Identities

The sum and difference identities can be used to determine the sine of an angle that can be written as the sum or difference of π/6 and another angle: sin(a + b) = sin(a)*cos(b) + cos(a)*sin(b) and sin(a – b) = sin(a)*cos(b) – cos(a)*sin(b).

### Double-Angle and Half-Angle Identities

The double-angle identity, 2*sin(π/6)cos(π/6) = sin(2*π/6) = sin(π/3), and the half-angle identity, sin(π/6/2) = ±√[(1 – cos(π/6))/2], are other important properties involving sin(π/6).

### Pythagorean Identity

The Pythagorean identity is a fundamental property of trigonometry that arises from the definition of sine and cosine using the unit circle. The identity states that for any real number θ,

$\sin^2(\theta) + \cos^2(\theta) = 1$

Let’s apply this identity to θ = π/6.

$$\sin^2\left(\frac{\pi}{6}\right) + \cos^2\left(\frac{\pi}{6}\right) = 1$$

We know that sin(π/6) = 1/2 and cos(π/6) = √3/2. Substituting these values into the identity, we have:

$$\left(\frac{1}{2}\right)^2 + \left(\frac{\sqrt{3}}{2}\right)^2 = 1$$

Solving this gives us 1/4 + 3/4 = 1, which simplifies to 1 = 1, confirming the identity.

So, the Pythagorean identity holds for θ = π/6, as it does for all real numbers θ.

These properties are not just mathematical curiosities; they play a crucial role in the solution of various problems in mathematics and its applied fields. By understanding these properties, we can manipulate and simplify expressions, solve equations, and make connections between different areas of mathematics.

## Applications

The value of sin(π/6), or sin(30°), which is 1/2, finds numerous applications across a wide array of disciplines. The profound simplicity and elegance of this value provide the foundation for more complex calculations and concepts in various fields.

### Trigonometry

In trigonometry, sin(π/6) is one of the fundamental trigonometric values used to calculate angles and distances. It helps in solving problems related to right triangles, such as finding the length of a side or the measure of an angle.

### Geometry

The sin(π/6) value is often utilized in geometric calculations. For instance, it is used to determine the height of an equilateral triangle when the length of one side is known, as sin(π/6) gives the ratio of the height to the length of the side.

sin(π/6) is utilized in navigation and geolocation systems. It assists in determining distances, angles, and trajectories, aiding in the accurate positioning and navigation of objects or vehicles.

### Physics

In the realm of physics, the sine function, including sin(π/6), plays a crucial role. It is instrumental in the study of simple harmonic motion, wave motion, and electromagnetic radiation. For instance, the sine function is used in the mathematical representation of waveforms, including light waves and sound waves. The phase difference between two waves, which can influence the resulting waveform, often involves the sine function.

### Engineering

In engineering fields, particularly in electrical and civil engineering, sin(π/6) holds notable importance. Electrical engineers often deal with alternating current (AC) circuits, where the voltage and current vary sinusoidally with time. The phase difference between voltage and current in an AC circuit can be modeled using the sine function. In civil engineering, the sine function helps calculate forces in structures, notably in the analysis of load effects on inclined members of a structure.

### Computer Science

In computer graphics and gaming, the sine function, including sin(π/6), is used in rendering and animating curves, rotations, and waves. This is particularly evident in the programming of physics engines for games, where sine functions are used to simulate natural motion or trajectories.

### Astronomy

The sine function also finds its use in astronomy, particularly in calculations involving Earth’s rotation and celestial navigation. As the Earth rotates, the angle between a celestial object and the observer changes, and this can be described using the sine function.

### Mathematics

Within mathematics, sin(π/6) often serves as a fundamental value in trigonometric identities and theorems. Its straightforward value is used in simplifying complex trigonometric expressions and equations.

### Music

Interestingly, the sine function, including sin(π/6), also has applications in music theory. Sound waves are sinusoidal, and the theory of harmonics, which explains the richness and complexity of sounds, relies heavily on trigonometric functions.

In conclusion, sin(π/6) might seem like a small cog in the vast machinery of mathematics, but it has wide-reaching applications. From enabling the construction of bridges and buildings, to helping render realistic graphics in video games, to contributing to our understanding of the universe, this simple yet powerful mathematical function significantly impacts various fields of study and professional disciplines.

## Exercise

### Example 1

#### Evaluating sin(π/6)

Evaluate the numerical value of sin(π/6).

### Solution

sin(π/6) is a fundamental value in trigonometry. From the unit circle or 30-60-90 triangle, we know that:

sin(π/6) = sin(180/6)

sin(π/6) = sin(30)

sin(π/6) = 1/2

### Example 2

#### Find the value of sin(7π/6)

Calculate the numerical value of sin(7π/6)

### Solution

Using the property of periodicity of the sine function (period = 2π), we see that:

sin(7π/6) = sin(π/6)

sin(7π/6) = sin(180/6)

sin(7π/6) = sin(30)

sin(7π/6) = 1/2

The solution has also been depicted in Figure-2.

Figure-2.

### Example 3

#### Calculating the value of x

Given the equation sin(x) = sin(π/6), solve for x.

### Solution

For this, we use the fact that the sine function is periodic with period 2π. Therefore, if:

sin(x) = sin(π/6)

then:

x = π/6 + 2nπ

or:

x = π – π/6 + 2nπ

x = 5π/6 + 2nπ

where n is any integer.

### Example 4

#### Evaluating sin(-π/6)

Compute the numerical value of sin(-π/6)

### Solution

Using the property of odd symmetry of the sine function (sin(-θ) = -sin(θ)), we have:

sin(-π/6) = -sin(π/6)

sin(-π/6) = -1/2

The solution has also been depicted in Figure-3.

Figure-3.

### Example 5

#### Using the Double-Angle Formula

Calculate the value of sin(2*π/6) using the double-angle formula

### Solution

The double angle formula is sin(2θ) = 2sin(θ) * cos(θ). So we have:

sin(2π/6) = sin(π/3)

sin(2π/6) = 2sin(π/6) * cos(π/6)

sin(2π/6) = 2(1/2)*(√3/2)

sin(2π/6) = √3/2

### Example 6

#### Using Half-Angle Formula

Determine sin(π/6/2) using the half-angle formula.

### Solution

The half angle formula is sin(θ/2) = ±√[(1 – cos(θ))/2]. So we have:

sin(π/6/2) = sin(π/12)

sin(π/6/2) = ±√[(1 – cos(π/6))/2]

sin(π/6/2) = ±√[(1 – √3/2)/2]

### Example 7

#### Evaluating sin(5π/6 + π/6)

Find the numerical value of sin(5π/6 + π/6).

### Solution

We use the sum formula sin(a + b) = sin(a)*cos(b) + cos(a)*sin(b). So we get:

sin(5π/6 + π/6) = sin(5π/6) * cos(π/6) + cos(5π/6) * sin(π/6)

sin(5π/6 + π/6) = 1/2 * √3/2 + -√3/2 * 1/2

sin(5π/6 + π/6) = 0

### Example 8

#### Evaluating $\sin^2\left(\frac{\pi}{6}\right) + \cos^2\left(\frac{\pi}{6}\right)$

Compute the numerical value for the given trigonometric function, $\sin^2\left(\frac{\pi}{6}\right) + \cos^2\left(\frac{\pi}{6}\right)$.

### Solution

We use the Pythagorean identity $\sin^2(\theta) + \cos^2(\theta) = 1$. So we have:

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

= 1/4 + 3/4

= 1

All figures are generated using MATLAB.