lispdoc - results for atan

(atan y &optional (x nil xp))
Function: Return the arc tangent of Y if X is omitted or Y/X if X is supplied.
 Mentioned in:
CLtL2 - 12.5.1. Exponential and Logarithmic Functions
CLtL2 - 12.5.2. Trigonometric and Related Functions
CLtL2 - 12.5.3. Branch Cuts, Principal Values, and Boundary Conditions in the Complex Plane
HyperSpec - Function ASIN, ACOS, ATAN
PCL - higher math
(tan number)
Function: Return the tangent of NUMBER.
 Mentioned in:
CLtL2 - 12.5.2. Trigonometric and Related Functions
CLtL2 - 12.5.3. Branch Cuts, Principal Values, and Boundary Conditions in the Complex Plane
HyperSpec - Function SIN, COS, TAN
PCL - higher math