sin(pi) and cos(pi/2) not zero

[ybh10]

This problem was discussed here: #447
The solution to use big numbers does not seem to work anymore.
math.config({number: 'BigNumber'});
math.evaluate('cos(pi/2)').toString() //=1.539082031431044993140174126710585339910740432566411533235469223e-64 != 0
Is there a way to do it now with a full expression?

[josdejong]

Both number and BigNumber are floating point numbers, so you can easily get round-off errors.

For displaying to a user, the easiest is to round the number to a limited number of digits.

Here some documentation: https://mathjs.org/docs/datatypes/numbers.html#roundoff-errors

[kgryte]

There are ways of handling this without requiring manual rounding in userland. Namely, dedicated APIs supporting argument reduction which allow for more accurate computation for larger inputs. One could re-implement in Math.js, or just rely on, e.g., stdlib, to address the above use case.