Let z1 = √2(cos 7pi/4 + i sin 7pi/4) and z2 = 2(cos 5pi/3 + i sin 5pi/3), how do you find z1/z2?

1 Answer
Apr 13, 2016

z1z2=12[cos(π12)+isin(π12)]

Explanation:

A complex number of form rcosθ+irsinθ can also be written as reiθ.

Hence, z1=2(cos(7π4)+isin(7π4))=2ei7π4

and z2=2(cos(5π3)+isin(5π2))=2ei5π3

Hence z1z2=22xei(7π45π3)=12ei(21π20π12)=12eiπ12

= 12[cos(π12)+isin(π12)]