Need help with Trig/angle question

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To convert a point from rectangular coordinates (1, -1) in the fourth quadrant to polar form, use the formulas r = √(x² + y²) and θ = arctan(y/x), adjusting for the quadrant. The angle can be expressed in the format θ = [7(π)/2] + 2n(π) by determining the appropriate reference angle and adding multiples of 2π as needed. If the arctan result is not a whole number, such as 53.1 degrees, it will also yield an irrational value in radians, making it impossible to express neatly in the desired format. Therefore, the conversion process requires careful consideration of both the angle and the quadrant. Understanding these principles is essential for accurate polar coordinate conversion.
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For example: if i have a point (1, -1) in the forth quadrant of the xy plane. How do you convert it to angle = [7(pie)/2]+2n(pie) format? i just forget how to do that part. Also, what if the answer for tan-1(angle) is not a whole #, ex: 53.1, then how do you do the conversion? Thank you.
 
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To convert from rectangular (x,y) to polar (r,theta):
r=Sqrt[x^2+y^2]
theta=arctan(y/x), after which you must consider the given quadrant

See wikipedia: http://en.wikipedia.org/wiki/Polar_...rting_between_polar_and_Cartesian_coordinates

If you get an irrational answer in degree form, it's probably going to be irrational in radians form as well, e.g. tan-1[4/3]~53.130deg~.927r. in this case, there's no neat a*Pi+2nPi form, where a is rational and n is integer.

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