The professor gave me this exercise, but since I am new in this subject I did not understand what he wants.

"In a single phase circuit Va=120 amplitude and 45degree as phase (written in polar form) and Vb = 100 amplitude and -15 phase.
Find Vba in polar form."

Does it mean that I have to do Vb-Va? or am I wrong?

 

Did the prof use \(\theta\) for "polar form you've written out above", or is he trying to get you to understand the difference between rectangular format (a±bi) and polar format \(a \theta \phi\)

 

The professor gave me this exercise, but since I am new in this subject I did not understand what he wants.

"In a single phase circuit Va=120 amplitude and 45degree as phase (written in polar form) and Vb = 100 amplitude and -15 phase.
Find Vba in polar form."

Does it mean that I have to do Vb-Va? or am I wrong?

I think you are right. I would interpret that as Vb-Va.