Double-Angle Calculator
Double-Angle with stated conventions, validation and a worked example.
Formula
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Angles are in degrees unless the unit selector says otherwise. Outputs are numerical approximations. A denominator with magnitude below 10⁻¹² is treated as singular.
Example Calculation
- Angle: 30 °
For θ=30°, sin60°=√3/2, cos60°=1/2, tan60°=√3.
Method references
Frequently asked questions
How do I use this calculator?
Enter angle. The result updates automatically. Use Reset to restore the example values.
What method does it use?
sin 2θ=2sinθcosθ; cos 2θ=cos²θ−sin²θ; tan 2θ=sin 2θ/cos 2θ. Angles are in degrees unless the unit selector says otherwise. Outputs are numerical approximations. A denominator with magnitude below 10⁻¹² is treated as singular.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.