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Sinclair Scientific question - Chris Chung - 09-01-2015 01:44 PM
Are there Sinclair Scientific owners here? I had created this emulator based on a software version and one of my kit builders had a question on the accuracy.
<quote>
But someting strange in happening : I put it in the sinclair mode and calculate here sin of 25 and the result wos 1,5720 Ex.00 (the same as on the on-line one, that you sended me), but the father Google said that it is - 0,1323. I know that the sinclair is well known for it´s inacuracy, but the minus seems little bit much... So, is this good resault on the sinclair ? Or I mess something more up? (I have tested the LED on different example 1-9 999 999 9 and I ensure that the LED work fine on the negative resault.)
</quote>
So I checked the web emulator and my hardware emulator and both got result of 2.4797 E -1 (google gives -0.13235... on SIN(25 radian)).
I want to know how should I make out of this (I am dumb on math).
If someone has a working Sinclair Scientific, can he / she make a run and see if my emulator is working properly?
C, 2, 5, E, 1, sin (as in ^, +)
And if they agree, what would be the impact of someone using this calculator for real work. (It was advertised as a calculator back then, not a toy)
Thanks.
RE: Sinclair Scientific question - EdS2 - 09-01-2015 03:54 PM
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/Sinclair_Scientific_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:
[attachment=2482]
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.)
RE: Sinclair Scientific question - Chris Chung - 09-02-2015 04:50 PM
thanks EdS, I should have read the manual throughout.