Reference · Math

math.tan

math.tan(num) -> float

What it does

The tangent of an angle in radians, as a float, as Python's math.tan. An angle in degrees is converted first with math.radians.

Examples

print(math.tan(0), math.tan(math.pi / 4), math.tan(1))print(math.tan(math.radians(45)), math.tan(-math.pi / 4))

0.0 0.9999999999999999 1.55740772465490230.9999999999999999 -0.9999999999999999

Edge cases

• Floating point: the tangent of 45 degrees is 0.9999999999999999. Round when a clean figure is wanted.
• math.pi / 2 is not exactly a right angle, so math.tan(math.pi / 2) is a huge number (about 1.6e16), not infinity and not an error.
• NaN gives NaN; an infinite angle is a domain error.
• math.tan(x) is math.sin(x) / math.cos(x) to within a last digit, which differs by platform: compare with math.isclose, not ==.

print(math.tan(math.radians(45)), round(math.tan(math.radians(45)), 10))print(math.tan(math.pi / 2) > 1e16, math.isfinite(math.tan(math.pi / 2)))print(math.tan(math.nan))print(math.isclose(math.tan(1), math.sin(1) / math.cos(1)))

0.9999999999999999 1.0true trueNaNtrue

Errors

inf or -inf is a runtime error (a domain error), not an error value: it stops the request. A value that is not a number is a runtime error too; a decimal is converted first with float.

print(math.tan(math.inf))

line 1: `math.tan`: math domain error (inf)

print(math.tan(dec("1")))

line 1: `math.tan` expects a number as argument 1, got dec (this works on floats: convert a dec with float(x))

Chaining

A slope from an angle, and the angle back with math.atan:

print(30 | math.radians | math.tan)print(30 | math.radians | math.tan | math.atan | math.degrees)

0.577350269189625729.999999999999996

See also

math.sin, math.cos, math.atan, math.atan2, math.radians, math.tanh

Edit this page on GitHub · every example's output was made by running it (tools/refcheck.mjs) · questions on Discord or r/quillo