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| author | Serhiy Storchaka <storchaka@gmail.com> | 2017-05-04 09:25:09 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2017-05-04 09:25:09 (GMT) |
| commit | dbaf746b6de0ee431c809d3175ab40ccc18898a8 (patch) | |
| tree | a7a07d3e2bde0a326e2c5fba7c2fce4396bdb1cd /Doc/library/math.rst | |
| parent | 7e4db2f253c555568d56177c2fd083bcf8f88d34 (diff) | |
| download | cpython-dbaf746b6de0ee431c809d3175ab40ccc18898a8.zip cpython-dbaf746b6de0ee431c809d3175ab40ccc18898a8.tar.gz cpython-dbaf746b6de0ee431c809d3175ab40ccc18898a8.tar.bz2 | |
bpo-29956: Improve the math.exp() related documentation. (#1073)
Diffstat (limited to 'Doc/library/math.rst')
| -rw-r--r-- | Doc/library/math.rst | 27 |
1 files changed, 18 insertions, 9 deletions
diff --git a/Doc/library/math.rst b/Doc/library/math.rst index 0c53b29..9e49463 100644 --- a/Doc/library/math.rst +++ b/Doc/library/math.rst @@ -42,15 +42,18 @@ Number-theoretic and representation functions *y*. On platforms that support signed zeros, ``copysign(1.0, -0.0)`` returns *-1.0*. + .. function:: fabs(x) Return the absolute value of *x*. + .. function:: factorial(x) Return *x* factorial. Raises :exc:`ValueError` if *x* is not integral or is negative. + .. function:: floor(x) Return the floor of *x*, the largest integer less than or equal to *x*. @@ -220,12 +223,15 @@ Power and logarithmic functions .. function:: exp(x) - Return e raised to the power *x*, where e = 2.718281... is the base - of natural logarithms. + Return *e* raised to the power *x*, where *e* = 2.718281... is the base + of natural logarithms. This is usually more accurate than ``math.e ** x`` + or ``pow(math.e, x)``. + .. function:: expm1(x) - Return ``e**x - 1``. For small floats *x*, the subtraction in ``exp(x) - 1`` + Return *e* raised to the power *x*, minus 1. Here *e* is the base of natural + logarithms. For small floats *x*, the subtraction in ``exp(x) - 1`` can result in a `significant loss of precision <https://en.wikipedia.org/wiki/Loss_of_significance>`_\; the :func:`expm1` function provides a way to compute this quantity to full precision:: @@ -290,10 +296,10 @@ Power and logarithmic functions Return the square root of *x*. + Trigonometric functions ----------------------- - .. function:: acos(x) Return the arc cosine of *x*, in radians. @@ -339,10 +345,10 @@ Trigonometric functions Return the tangent of *x* radians. + Angular conversion ------------------ - .. function:: degrees(x) Convert angle *x* from radians to degrees. @@ -352,6 +358,7 @@ Angular conversion Convert angle *x* from degrees to radians. + Hyperbolic functions -------------------- @@ -440,23 +447,25 @@ Constants .. data:: pi - The mathematical constant π = 3.141592..., to available precision. + The mathematical constant *π* = 3.141592..., to available precision. .. data:: e - The mathematical constant e = 2.718281..., to available precision. + The mathematical constant *e* = 2.718281..., to available precision. + .. data:: tau - The mathematical constant τ = 6.283185..., to available precision. - Tau is a circle constant equal to 2π, the ratio of a circle's circumference to + The mathematical constant *τ* = 6.283185..., to available precision. + Tau is a circle constant equal to 2\ *π*, the ratio of a circle's circumference to its radius. To learn more about Tau, check out Vi Hart's video `Pi is (still) Wrong <https://www.youtube.com/watch?v=jG7vhMMXagQ>`_, and start celebrating `Tau day <http://tauday.com/>`_ by eating twice as much pie! .. versionadded:: 3.6 + .. data:: inf A floating-point positive infinity. (For negative infinity, use |