Accuracy of sinh and complex cos/sin #247
This patch replaces
This 5th degree taylor expansion of sinh is quite far off when you get close to -1 or 1. For example, for x = 0.99, it’s off by about 1.87e-4. I assume that’s dramatically more error than you want in a math library.
For a graph of the error, here’s Wolfram Alpha: http://www.wolframalpha.com/input/?i=sinh%28x%29+-+%28x+%2B+%281%2F6%29+*+x%5E3+%2B+%281%2F120%29+*+x+%5E+5%29+from+-1+to+1
The GNU Scientific Library uses the degree 17 Taylor expansion for computing sinh in the range [-1, 1]: