Property	Value
Hex Value	`$1C`
Categories	Angle Catalog > R
Localizations	FR: `R►Pθ(`

`R►Pθ(`

Overview

Returns θ, given rectangular coordinates x and y or a list of rectangular coordinates.

Availability: Token available everywhere.

Syntax

R►Pθ(x,y)

Arguments

Name	Type	Optional
θ
x
y

Location

2nd, angle, ANGLE

Description

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 1^ʳ:

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.

Source: parts of this page were written by the following TI|BD contributors: burr, DarkerLine, GoVegan, thornahawk.

History

Calculator	OS Version	Description
TI-82	1.0	Added

Authors: Adrien Bertrand

R►Pθ(