Hey, can someone help with the following?
let z = (1+ sqrt(3)i ) and w = (1+i). Evaluate zw and hence show that cos (7*pi/12) = (1 - sqrt(3))/2*sqrt(2)
Thanks
Good! What did you get? And do you know how to use "polar form" to multiply two complex numbers? The argument of that product is equal to the sum of the arguments of the two numbers. And, of course, $\displaystyle r cos(\theta)$ is the real part of the number with modulus r and argument $\displaystyle \theta$.