Answer to Question #44245 in Complex Analysis for ch

Question

w=(3-i)/(2i-1) solving this i get that w= -i-1 now i want to express w in polar form: r=sqrt2

but can you explain why arg(w)= -3pi/4 ? when arctan(1) = pi/4 (how do they get -3pi/4)

and if arg(w)= -3pi/4 can i than write 5pi/4 instead

and z^4=w and how to draw the solutions in the complex plane