The Half Angle Calculator is a tool used to determine the value of the half angle of a given angle. The half angle is simply half of the given angle, and it is usually expressed in radians. The calculator can be useful in various fields, such as trigonometry, geometry, and physics.

**Enter Information**

Enter an angle in degrees to find its half angle:

sin(θ/2) = ±√[(1-cos(θ))/2]

cos(θ/2) = ±√[(1+cos(θ))/2]

tan(θ/2) = sin(θ)/(1+cos(θ))

## What is Half Angle Calculator

A half angle calculator is a tool that can be used to find the values of trigonometric functions (sine, cosine, and tangent) for half of a given angle. This can be useful in solving problems in trigonometry, calculus, and other areas of mathematics and science.

The formulas for half angle trigonometric functions can be derived using the double angle formulas for sine, cosine, and tangent. For example, the formula for the half angle of sine is:

sin (θ/2) = ± √[(1 – cos θ)/2]

where θ is the angle in radians, and the sign of the result depends on the quadrant in which the angle lies.

Similarly, the formulas for the half angles of cosine and tangent are:

cos (θ/2) = ± √[(1 + cos θ)/2] tan (θ/2) = ± √[(1 – cos θ)/(1 + cos θ)]

A half angle calculator can simplify the process of finding these values by performing the necessary calculations automatically. Simply enter the angle in radians into the calculator, and it will return the values of sine, cosine, and tangent for half of that angle. Some calculators may also allow you to choose the sign of the result based on the quadrant of the original angle.

## How to use half angle calculator?

The specific steps to use a half angle calculator may depend on the specific calculator you are using. However, in general, you can follow these steps to use a half angle calculator:

- Enter the value of the angle (in radians) for which you want to find the half angle.
- Select the trigonometric function (sine, cosine, or tangent) for which you want to find the half angle.
- Click the “calculate” button or press “enter” to get the result.

Once you have the result, you can use it in your calculations as needed. Some half angle calculators may also provide additional information, such as the quadrant in which the original angle lies or the exact value of the result (if it is a non-decimal number).

It is important to note that when using a calculator, you should be familiar with the underlying concepts and formulas of half angle trigonometry, and be able to verify the results obtained using the calculator.

## Half Angle Formulas

The half angle formulas are used to find the values of trigonometric functions for half of a given angle. There are half angle formulas for sine, cosine, and tangent, which are derived from the double angle formulas for these functions. The half angle formulas are as follows:

Sine Half Angle Formula:

sin(θ/2) = ±√[(1 – cosθ)/2]

where θ is the original angle and the sign of the result depends on the quadrant in which the angle lies.

Cosine Half Angle Formula:

cos(θ/2) = ±√[(1 + cosθ)/2]

where θ is the original angle and the sign of the result depends on the quadrant in which the angle lies.

Tangent Half Angle Formula:

tan(θ/2) = ±√[(1 – cosθ)/(1 + cosθ)]

where θ is the original angle and the sign of the result depends on the quadrant in which the angle lies.

It is important to note that the choice of sign (positive or negative) for the half angle depends on the quadrant in which the original angle lies. To determine the sign, you can use the quadrant in which the original angle lies and the trigonometric ratios of that angle.

## How to calculate half angle and example?

To calculate the half angle of an angle θ, you can use the following steps:

- Use the given angle θ to calculate the value of the cosine of the angle, cos(θ).
- Use the formula for the cosine half angle, cos(θ/2) = ±√[(1 + cos(θ))/2], to calculate the value of the cosine of the half angle, cos(θ/2).
- If the original angle θ is in the first or fourth quadrant, choose the positive sign for the cosine half angle. If the original angle is in the second or third quadrant, choose the negative sign for the cosine half angle.
- Once you have the value of the cosine half angle, you can use the half angle formula for the other trigonometric functions (sine and tangent) as follows:

sin(θ/2) = ±√[(1 – cos(θ))/2] (with the same sign as the cosine half angle) tan(θ/2) = sin(θ/2)/cos(θ/2)

Here’s an example of calculating the half angle:

Let’s say we want to find the half angle of an angle of 60 degrees.

- Calculate the cosine of 60 degrees: cos(60) = 1/2
- Use the formula for the cosine half angle: cos(θ/2) = ±√[(1 + cos(θ))/2] = ±√[(1 + 1/2)/2] = ±√(3/4) = ±(√3)/2. Since 60 degrees is in the first quadrant, we choose the positive sign for the cosine half angle: cos(30) = (√3)/2
- Use the sine half angle formula: sin(θ/2) = ±√[(1 – cos(θ))/2] = ±√[(1 – 1/2)/2] = ±(1/2) Since the original angle is in the first quadrant, we choose the positive sign: sin(30) = 1/2
- Use the tangent half angle formula: tan(θ/2) = sin(θ/2)/cos(θ/2) = (1/2)/[(√3)/2] = √3/3

Therefore, the half angle of 60 degrees is 30 degrees, and the values of sine, cosine, and tangent of the half angle are 1/2, (√3)/2, and √3/3, respectively.