#"to convert into "color(blue)"trigonometric form"#
#"that is " x+yitor(costheta+isintheta)# where
#color(red)(bar(ul(|color(white)(2/2)color(black)(r=sqrt(x^2+y^2))color(white)(2/2)|)))#
#"and " color(red)(bar(ul(|color(white)(2/2)color(black)(theta=tan^-1(y/x);-pi< theta<=pi)color(white)(2/2)|)))#
#"here " x=-3" and " y=-2#
#rArrr=sqrt((-3)^2+(-2)^2)=sqrt13#
#"now " -3-2i" is in the 3rd quadrant so must ensure that"#
#theta" is in the 3rd quadrant"#
#theta=tan^-1(2/3)=0.588larrcolor(red)" related acute angle"#
#rArrtheta=-pi+0.588~~-2.55larrcolor(red)" in 3rd quadrant"#
#rArr-3-2i=sqrt13(cos(-2.55)+isin(-2.55))#
#• color(orange)" Reminder" cos(-theta)=costheta ; sin(-theta)=-sintheta#
#rArr-3-2i=sqrt13(cos(2.55)-isin(2.55))#
