converting EM wave from exponent to sine cosine expression question

[yefj]

Hello,I am trying to convert an exponential expression into their sine and cosine representation as shown below.
how do i proceed from the expression bellow into the expressions I got at 2.5.2?

https://eceweb1.rutgers.edu/~orfanidi/ewa/ch02.pdf

Thanks.

 

[D.A.(Tony)Stewart]

Use Euler's formula e^jθ=cos⁡(θ)+jsin⁡(θ)