Angle Addition and Subtraction

°
Enter angle α in °.
°
Enter angle β in °.
Math

Angle Addition and Subtraction with stated conventions, validation and a worked example.

Formula

sin(α±β)=sinαcosβ±cosαsinβ; cos(α±β)=cosαcosβ∓sinαsinβ

Example Calculation

Example inputs
  • Angle α: 45 °
  • Angle β: 30 °

45°+30°=75°, whose sine is (√6+√2)/4≈0.9659.

Frequently asked questions

How do I use this calculator?

Enter angle α, angle β. The result updates automatically. Use Reset to restore the example values.

What method does it use?

sin(α±β)=sinαcosβ±cosαsinβ; cos(α±β)=cosαcosβ∓sinαsinβ. 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.