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# Double angle formula calculator

To find the value of sin2x, cos2x, or tan2x, put the angle in the double angle formula calculator.

## Double Angle Calculator

The double angle identity calculator finds the value of a double angle for any trigonometric function if the value of an angle is provided. This calculator can compute values of:

`Sin2x`

`Cos2x`

`Tan2x`

## What is a double angle?

Double angle, as the words imply, means to increase the size of the angle to twice its size. It simply means two times of a trigonometric angle i.e. **2x **in terms of **x**. Double-angle identities are used to simplify trigonometric calculations.

## Double angle formula

The main formulas used to find a double angle are:

`Sin2x = 2 (sinx).(cosx)`

`Cos2x= 2.cos`

^{2}x -1- t
`an2x = (`

`2.tanx)/(1 - tan`

^{2}x)

You can also calculate the half-angle of trigonometric identities by using our half angle identity calculator.

## How to find a double angle?

You can learn to find the double angle through an example.

*Example*

What is the double angle for **sin 40****°**?

*Solution*

**Step 1: **Write the formula of **sin2x**.

`Sin2x = 2 (sinx).(cosx)`

**Step 2:** Put the value of the angle into the formula.

Sin2x = 2 (sin 40).(cos 40)

= 2 (0.642)(0.766)

`= 0.9836`