Re: How does the calculator calculate cos(x)?
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Re: How does the calculator calculate cos(x)?
The TI calculates cos(x) by saying to itself, "hmmm . . . what is x?"
If x is a multiple of 90 degrees it goes to a short look-up table where it finds
0,1 or -1 and it's done.
Otherwiese, it divides the angle by 360 degrees, makes a note of what quadrant
the resulting angle is in and replaces x by the reference angle (angle with horiz
axis.) Then, taking out pencil, paper, compasses and ruler it constructs a right
triangle with angle x. Then it says, "Oh, W, X, Y, ZED!! Whatever put it in my
head?! I was in in radian mode when I thought I was in degree mode!!" So it
repeats the above process with x in degrees, and carefully measuring the lengths
of the sides adjacent that angle assigns (+/- depending on what quadrant the angle
was in) the value of the ratio of shorter length over longer to the cos(x) and
displays this value on the homescreen.
Or maybe it sums the Taylor series. Or maybe there's a look-up table. Is such
information proprietary? I'd like to know too!
ArchDluxxx wrote:
> I would like to learn how the TI's actually calculate cos(x). Can anybody help
> me!!!
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