Why R2018a and 2019b give different results for cosine (cosd) function?

Hello,

given the following code

a = single(-91.5380859);
b = cosd(a);
c = double(b)

I got different results for c depending on the matlab version I use.

2018a: -0.026841441169381

2019b: -0.026841439306736

I figured out that the binary representation for b is different in the last bit:

2018a: 10111100110110111110001010010101

2019b: 10111100110110111110001010010100

So assume that the funtion cosd is rounding in different ways. But why?

Thanks.

Answer 1

[Steven Lord]

I suspect the answer was changed by the fix for bug 1839169.