Latex Symbol for the inverse (negative) angle of Complex Number? [duplicate]

Is there a Latex symbol to represent the inverse angle of a complex number? Since, from what i see, this isn't very well known, I'll post a picture of my math book which uses it below (Engineering Mathematics - Stroud). Thanks.

marked as duplicate by Werner, user36296, JPi, Zarko, FranFeb 22 '17 at 2:55

• You can use the information provided in How to draw a partial or incomplete box around one or more words within a paragraph to create your own \invangleb{120} and \invanglet{135} (say). – Werner Feb 22 '17 at 0:58