Sinclair Scientific question

[EdS2]

According to the manual, the input range for sin() is from 0 to pi/2 - so 25 radians is out of range.
http://www.datamath.net/Manuals_Others/S...fic_GB.pdf

But the accuracy is about as good as a slide rule, maybe a little better, so long as you stay within the allowed ranges - and as such, could be a useful calculator for some purposes. You'll almost certainly need pencil and paper to store intermediate results.

I get the same result with my Sinclair:
   

If you do your own range reduction - enter pi, multiply by 8, subtract 25 - then you can take the sin, and you'll get 1.3218E-01 which is pretty close to correct. (It's not possible, I think, to post-multiply by a negative number, so you'll have to take account of the sign yourself.)