If someone (captain black) could help me out here asap as i need to give this question in in twelve hours time

Thanks in advance

a) If F = mlog(sinhz) show that Im{F} is consant on the lines y=pi/2 and
y= -pi/2

In between these two parts i have shown that F is the complex potential for a source of strength 2m(pi) at the origin in the presence of straight boundaries a distance pi apart

b) Find the fluid velocity at a large distance from the source?