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The following formula are half angle formulas for **sin, cos,** and *tan***respectively.**

**sin (θ / 2) = √ 1 – cos θ / 2**

**cos (θ / 2) = √ 1 + cos θ / 2**

**tan (θ / 2) = 1 – cos θ / sin θ**

The half angle calculator is used to measure the trigonometric values for half angle (θ/2). This calculator aids in evaluating the trigonometric value by using the half angle formulas. Our half angle formula calculator reduces the complication in the trigonometric functions by automating the process.

To use our half angle formula calculator for evaluating half angle for trigonometric identities, follow these steps:

- Enter the
**θ****angle**in degree the text box. - Click on the trigonometric function you want to calculate, i.e.,
*sin, cos, or tan.*

You can use our double angle calculator if you need to calculate the **double angle**.

Let’s calculate half angle step by step with an example.

Calculate the half angle for ** sin, cos, and tan** for a

To find half angle for ** sin, cos, tan,** follow the steps below:

** Step 1: **Substitute the given angle in the half angle formula for

**sin θ/2 = √1 – cos θ / 2**

= √1 – cos (120) / 2

= √1 – (-0.5) / 2

= 0.866

**sin θ/2 ****= 0.866**

** Step 2: **Place the given angle in the half angle formula for

**cos θ/2 = √1 + cos θ / 2**

= √1 + cos (120) / 2

= √1 + (-0.5) / 2

= 0.5

**cos θ/2 ****= 0.5**

** Step 3: **Substitute the given angle in the half angle formula for the

**tan θ/2 = 1 – cos θ / sin θ**

= 1 – cos (120) / sin (120)

= 1 – (-0.5) / (0.866)

= 1.73205

**tan θ/2 ****= 1.73205**

The half angle calculator exact value will be the same as calculated by the above formulas.

- What Are Half Angle Identities?. Sciencing.com
- Half-Angle Formulas -- from Wolfram MathWorld.
- How to Use Half-Angle Identities to Evaluate a Trig Function - dummies.com
- Bourne, M. (2020). 4. Half Angle Formulas. Intmath.com