Free · Trigonometry calculators 📐

Cosine of an Angle with Near-Zero Snapping

No. Its cosine is a read-only value displayed in the result note. Any real angle is accepted, including values outside triangle angles. Values with absolute cosine below 1e−15 are snapped to zero.

Formula & worked example
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Calculator inputs

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How to use this calculator

Enter the known values in the units shown. Results update as you type.
Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

Example in initial displayed units: Angle 90 gives Cos angle 0.

cos θ; output is zero when |cos θ| < 10⁻¹⁵

Worked example

Enter these known values and leave the other values blank.

Angle: 90 deg

Result: Cosine of 90 deg equals 0.

Assumptions and limitations

Angles can be any real value, not only an acute triangle angle. The cosine is periodic and dimensionless. The captured workflow snaps values with absolute cosine below 1e−15 to zero. Cosine is read-only here; an inverse-angle control is not provided.
Use compatible units and enough independent values. Clear unknowns before solving backward. Original reference drawings are schematic and do not scale to entered values.

Common questions

Does this cosine tool solve backward for an angle?