I am building trigonometric tables for efficiency. This is for a program, but seeing as programmers can't answer this, I am wondering if you can.
The problem I have encountered is in building a trig table for the arctangent formula. You see, a trig table for sine would look like this:
sin_table -> 0.6819983601...
As you can see, sine of 43 degrees would return 0.6819983601. This is used to increase performance in trig for programs.
How can I calculate the angle between 2 points and a horizontal without the $\arctan$ function?
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That will not work. I do not have access to any arc functions, but the other trig functions I do have access to.
As depicted below, P2 and P1 would be the 2 points, with the angle (Thick red line) goes from the horizontal +x axis, to the line P1P2.
I am not trying to build a trig table for the arctan. That would be horribly inefficient and costly on memory. I am just trying to figure out how to calculate it with a function, which should be faster (hopefully) than the bloated existing one. (The pre-existing one can take up to 50 times longer than even complex equations in this language).