Cos Calculator

The cosine function (cos) is a fundamental trigonometric function. It relates an angle of a right triangle to the ratio of the adjacent side to the hypotenuse. This calculator instantly computes cos(x) for any angle in degrees or radians.

1. Enter your angle value in the input field
2. Select DEG for degrees or RAD for radians
3. The result updates automatically as you type
4. View exact values for special angles when available

• Calculate cosine for any angle value
• Support for both degrees and radians
• π notation support (e.g., π/3, π/6)
• Exact values for special angles
• Shows secant (sec = 1/cos) as related value
• Real-time calculation

What is the range of cosine function?

The cosine function always returns values between -1 and 1, inclusive. cos(x) ∈ [-1, 1].

What is cos(0°)?

cos(0°) = 1. This is the maximum value of the cosine function.

What is the relationship between sin and cos?

sin(x) = cos(90° - x) and cos(x) = sin(90° - x). Also, sin²(x) + cos²(x) = 1.