- #1
Aerospace93
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Homework Statement
Find the polar form for zw by first putting z and w into polar form.
z=2√3-2i, w= -1+i
Homework Equations
Tan-1(-√3/3)= 5∏/6
The Attempt at a Solution
r= √[(2√3)2+(-2)2]=4
tanθ= -2/(2√3)=-1/√3=-√3/3=> acording to above... tan-1(-√3/3)= 5∏/6
so, in polar form z should be 4[cos(5∏/6)+isin(5∏/6)]...
However, in the markscheme as well as in another source i have (thus me deducing there was no coincidence) they've put 4[cos(-∏/6)+isin(-∏/6)].
I understand how tan(5∏/6) and tan(-∏/6) both equal(-√3/3)... though that's not the case for when it comes to cos(5∏/6) and cos(-∏/6).
So i would appreciate it if someone explained to me where i have gone wrong... and i think the question is pretty clear but if you think i haven't explained myself correctly go forth and tell me!