2.1.963 Part 1 Section, IMARGUMENT

a.   The standard does not fully specify how the angle θ is calculated.

Office calculates angle θ as ATAN2(x,y).

b.   The standard does not specify how function arguments map to formula variables.

Office maps x + yi to argument complex number, and theta to ATAN2(x,y).

c.   The standard states that the complex number can be in the form x+yi.

Office accepts complex numbers in the form x+yi and x+yj.