determining the Argument of z

[curry_bro]

how exactly do you figure this out? i understand the concept of determining the |z| and other basic complex number functions, but i dont really understand when you use sin, cos and tan, and how you incorporate 'a' and 'b' into the answer? :S (z=a+bi)

[TrueTears]

draw the point on an argand diagram, then just find the angle made with the positive x axis if the point is in quadrant 1 or 2 (with a clockwise orientation), if in quadrant 3 or 4 then find the angle made with the positive x axis but with an anticlockwise orientation

[curry_bro]

oh ok :S i still dont seem to get it though. could somebody please complete the question that ive attached? im seriously a novice spech student...

[Jenny_2108]

oh ok :S i still dont seem to get it though. could somebody please complete the question that ive attached? im seriously a novice spech student...

Arg(z) is calculated from tan(theta), so after you find z=a+bi => tan(theta)=b/a => find theta by drawing the argand diagram out

[curry_bro]

so arg(z) is always calculated by tan(theta) regardless of which quadrant? obviously, the value of theta will be different.

[TrueTears]

nope you don't have to use the tan function to find argument (and it get's confusing when you do use it mechanically), best method is always to sketch a diagram and use the definition of Argument

[curry_bro]

dont worry guys i think i get it now! hahaha its pretty easy, but i havent done GMA, so its a tad confusing at first!!