Find the sine, cosine, and tangent of an angle. Enter the angle and its unit.
Usage Tip
On the unit circle, cosine is the x-coordinate and sine is the y-coordinate of the angle’s point.
tan = sin ÷ cos
Tangent is undefined where cosine is zero (90, 270 degrees).
All three primary ratios are shown.
Tangent is undefined at 90 degrees and every 180 degrees after.
Sine, cosine, and tangent relate an angle in a right triangle to the ratios of its sides. Sine is the opposite side over the hypotenuse, cosine is the adjacent side over the hypotenuse, and tangent is the opposite side over the adjacent side. The same values extend to any angle through the unit circle.
Sine and cosine always lie between minus 1 and 1, while tangent can be any value and is undefined at 90 degrees and 270 degrees, where the cosine is zero. Check that the unit matches the angle you enter, since 30 degrees and 30 radians give very different results. Trigonometric values are used for slopes, forces, waves, and finding heights from angles.