[Octave-bug-tracker] [bug #48307] sinc loses precision for large arguments

[SUDHIR KUMAR SUMAN]

Follow-up Comment #32, bug #48307 (project octave):

I think that there is a problem with the accuracy of the sine function as
IN OCTAVE
>> sind(45)
ans =  0.70711
but in real sin(45) = 1/sqroot(2) = 7071067812;
>> sind(60)
ans =  0.86603
but it value should be sqroot(3)/2 = 0.8660254038.
 It is clear that sin is missing its accuracy only at its 5th place of
decimal.
So first sin function needs to be corrected as it might be possible that while
expanding the 
sine function in tailor series expansion for writting the code only upto few
terms are considered but we need to consider upto more terms(approx 100) to
get value correct upto 20 places of decimal.I have written code for sine
function in c++ and it is giving correct value upto 20 places of
decimal.Please correct me if I am wrong and 
If this is the correct issue why sinc() is not that much accurate for large
input value than I wil start  writing for sinc() into .m language. 


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