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How does atan2 work when getting angle of a?
This also suggests that your interpretation has mixed up the positive and negative 90 degree directions but is otherwise fine. Just to answer you question simply: arctangent function atan2 (y,x) uses the sign of BOTH parameters to determine the quadrant of the angle in the range -PI to +PI (-180 deg to +180 deg).
Which is the correct value for atan2 ( a, B )?
A positive result represents a counterclockwise angle from the x-axis; a negative result represents a clockwise angle. ATAN2 (a,b) equals ATAN (b/a), except that a can equal 0 in ATAN2. If both x_num and y_num are 0, ATAN2 returns the #DIV/0! error value.
How to change the argument of atan2 to PR ARG?
That is, atan2 (y, x) = Pr arg (x + yi) = Arg (x + yi). The argument could be changed by an arbitrary multiple of 2π (corresponding to a complete turn around the origin) without making any difference to the angle, but to define atan2 uniquely one uses the principal value in the range
What is the range of the arctan function atan2?
In terms of the standard arctan function, whose range is (−π/2, π/2), it can be expressed as follows: The following expression derived from the tangent half-angle formula can also be used to define atan2 : This expression may be more suited for symbolic use than the definition above.
Which is the inverse of math.atan2?
Given angle (in degrees) and the vector length, len, you can derive dx and dy by: Simple Google search threw this up, and the guy who asked the question said it solved it. If you are using the coordinate system where y gets bigger going down the screen and x gets bigger going to the right then you should use:
Is the Lua inverse of math.atan2 correct?
It will be correct until you hit 180 then as it should go beyond 180 (i.e. 187) it will invert it to a negative number going down from -180 to 0 as you get closer to 360. To correct for this we check to see if the angle is less than 0 and if it is we add 360 to give us the correct angle.
When to add 360° to the answer from atan2?
Just add 360° if the answer from atan2 is less than 0°. Or if you don’t like branching, just negate the two parameters and add 180° to the answer.