Trigonometry
Cosine Double Angle
cos(2θ) using the double-angle identity.
Formula
Formula
cos 2θ = cos2θ − sin2θ
Variables
| Symbol | Definition | Type & range | Units | Role |
|---|---|---|---|---|
| θ | angle (deg) | computed result | — | result |
Try it yourself
Interactive calculator
Worked examples
Example 1
Givenangle θ (deg) = 30
Result0.5
Example 2
Givenangle θ (deg) = 60
Result-0.5