https://issues.dlang.org/show_bug.cgi?id=15169

          Issue ID: 15169
           Summary: Add more trig functions to std.math
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: phobos
          Assignee: nobody@puremagic.com
          Reporter: jack@jackstouffer.com

The following functions should be included in std.math, even if they can be made from the existing functions, it makes code more readable and easier to write if they are in the std lib:

inverse sine
inverse cosine
inverse tangent
secant
inverse secant
cosecant
inverse cosecant
cotangent
inverse cotangent

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