New params-returns format.

doc/gumath/trigonometry/index.rst

@@ -11,7 +11,7 @@ sin
 
 Trigonometric sine, element-wise.
 
-:param x: `(array_like)` Angle, in radians (:math:`2\\pi` rad equals 360 degrees).
+:param x: `(array_like)` Angle, in radians (:math:`2\pi` rad equals 360 degrees).
 
 :returns: `(array_like)` The sine of each element of x.
 
@@ -45,10 +45,4 @@ Example
    >>> from xnd import xnd
    >>> x = [0.0, 45 * 3.14159/180, 90 * 3.14159/180]
    >>> gm.cos(xnd(x))
-   xnd([1.0, 0.70710, 6.12323e-17], type='3 * float64')
-
-.. math::
-
-    n_{\mathrm{offset}} = \sum_{k=0}^{N-1} s_k n_k
-
-Otra formula
+   xnd([1.0, 0.70710, 6.12323e-17], type='3 * float64')