Double angle formula calculator

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


Give Us Feedback

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

Double angle formula

The main formulas used to find a double angle are:

  • Sin2x = 2 (sinx).(cosx)
  • Cos2x= 2.cos2x -1
  • tan2x = (2.tanx)/(1 - tan2x) 

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.


What is the double angle for sin 40°?


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

Allmath loader
AdBlocker Detected!

To calculate result you have to disable your ad blocker first.