The R►Pθ( Command Command Summary

R►Pθ( calculates the angle coordinate (in polar coordinates) given the Cartesian coordinates.

Command Syntax

R►Pθ(x,y)

Press:

1. 2nd ANGLE to access the angle menu.
2. 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.

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°`
```

.