Hello everyone, I'm having a bit of trouble with using the argument function with DeMoivres formula. I have the question: z8= 16 and am meant to find the solution using DeMoivre's formula (zn=rn(cosn(Θ) +isinn(Θ)) ). The problem is, I have no idea what an argument function is or how to find it. I've read around a bit and found that root(a2+b2)= r and that tan-1(b/a) =arg but as you can see, I only have a (16) so that b=0, so is the argument then, tan-1(0)? I have several problems and they all have a but no b. However, in the answer section, they all have arguments. What the heck am I doing wrong? 2. Relevant equations I can do this one: z3=-1 as it has no argument (though I don't know why), and is just a matter of plugging in numbers. z3=-1 z3=1(cos(Θ)+isin(Θ) z=3√(1)(cos(Θ)+isin(Θ))1/3 z=1(cos(2kπ)+isin(2kπ)1/3 z=1(cos(2kπ/3)+isin(2kπ/3) and then, since it has no argument, k can equal 0, +/-1, +/-2, +/-3 etc..., you plug in the k and solve. 3. The attempt at a solution I haven't gotten very far with this one z8=16 z8= 168(cos8(Θ)+isin8(Θ)) or if I do it the other way z=8√(16)(cos(2kπ)+isin(2kπ))1/8 z=8√(16)(cos(2kπ/8)+isin(2kπ/8)) and I can't insert anything for k, because I don't know the argument. I know I sound like a real novice at math (I am), but I hope someone can help me! Thank you so much in advance!