How to Calculate Cos
What is Cos?
The cosine function (cos) is the ratio of the adjacent side to the hypotenuse in a right triangle, or the x-coordinate on the unit circle. Cosine is the "horizontal component" of an angle, while sine is the vertical component.
Formula
- In
- adjacent / hypotenuse — adjacent / hypotenuse
Step-by-Step Guide
- 1In a right triangle: cos(θ) = adjacent / hypotenuse
- 2On the unit circle: cos(θ) = x-coordinate at angle θ
- 3cos(θ°) = cos(θ × π/180)
- 4Key identity: sin²(θ) + cos²(θ) = 1 (Pythagorean identity)
Worked Examples
Frequently Asked Questions
What is Cos Calc?
The cosine function (cos) is the ratio of the adjacent side to the hypotenuse in a right triangle, or the x-coordinate on the unit circle. Cosine is the "horizontal component" of an angle, while sine is the vertical component
How accurate is the Cos Calc calculator?
The calculator uses the standard published formula for cos calc. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.
What units does the Cos Calc calculator use?
This calculator works with inches. You can enter values in the units shown — the calculator handles all conversions internally.
What formula does the Cos Calc calculator use?
The core formula is: In a right triangle: cos(θ) = adjacent / hypotenuse. Each step in the calculation is shown so you can verify the result manually.
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