First we add the complex numbers
#(1-5i)+(-2+i)=#
#=(1-2)+(-5i+i)#
#=-1-4i#
Convert to trigonometric form
for complex number #a+ib#
#a+ib=sqrt(a^2+b^2)*[cos(tan^-1(b/a))+i sin (tan^-1(b/a))]#
so we let #a=-1# and #b=-4#
#-1-4i=#
#sqrt((-1)^2+(-4)^2)*[cos(tan^-1((-4)/(-1)))+i sin (tan^-1((-4)/(-1)))]#
In the complex rectangular coordinate system, this is located at the 3rd quadrant
#sqrt17[cos(tan^-1 ((-4)/(-1)))+i sin (tan^-1 ((-4)/(-1)))]#
#sqrt17[cos(4.4674103172578)+i sin (4.4674103172578)]" ""#Radian
#sqrt17[cos(255.96375653207^@)+i sin (255.96375653207^@)]#
have a nice day !
