TI-BASIC:R Ptheta
Command Summary
R►Pθ( calculates the angle coordinate (in polar coordinates) given the Cartesian coordinates.
Command Syntax
R►Pθ(x,y)
Menu Location
Press:
- 2nd ANGLE to access the angle menu.
- 6 to select R►Pθ(, or use arrows and ENTER.
TI-83/84/+/SE
1 byte
R►Pθ( (Rectangular to polar θ) takes the (x,y) (Cartesian) coordinate, and returns the angle that the ray from (0,0) to (x,y) makes with the positive x-axis. This is the θ-coordinate of the same point in (r,θ) (polar) mode. The identity used for this conversion is tan(θ)=y/x, with the correct inverse being chosen depending on the quadrant that the point is in. The range of the angle returned is -π<θ≤π. R►Pθ( can also be used on lists.
R►Pθ( is equivalent to the atan2() instruction seen in C/++ and FORTRAN.
R►Pθ(3,4)
.927295218
tanֿ¹(4/3)
.927295218
R►Pθ(0,{1,-1})
{1.570796327, -1.57096327}
R►Pθ( is affected by Degree and Radian mode in its output, which is an angle measured in degrees or radians respectively.
Advanced Uses
If you want the result to always be a radian angle, regardless of mode settings, you can divide the result by 1r:
R►Pθ(x,y)/1^^r
If you want the result to always be a degree angle, regardless of mode settings, you can divide the result by 1°:
R►Pθ(x,y)/1°
Error Conditions
- ERR:DATA TYPE is thrown if you input a complex argument.
- ERR:DIM MISMATCH is thrown if two list arguments have different dimensions.
