How would I find the standard form of the complex number 9(cos((7pi)/6)=isin((7pi)/6))9(cos(7π6)=isin(7π6))?

1 Answer
Oct 9, 2015

Just evaluate the trigonometric functions and expand to get -(9sqrt(3))/2-9/2 i93292i (standard form for a complex number is a+bia+bi, where a,b\in RR)

Explanation:

Note that cos((7pi)/6)=-sqrt(3)/2 and sin((7pi)/6)=-1/2. Therefore

9(cos((7pi)/6)+i sin((7pi)/6))=9(-sqrt(3)/2-i 1/2)

=-(9sqrt(3))/2-9/2 i