5b de moivres theorem

[Saoirse09]

I need help with 5b I have 5a

 

[Deleted member 4993]

I need help with 5b I have 5a View attachment 22811

5b can be answered as a "consequence" of 5a.

Please share your solution of 5a.

 

[Saoirse09]

Here’s my answer to 5a it is correct the back of the book says p=8 q=-4 r=-3

 

[Steven G]

 

[Harry_the_cat]

You seem to be on the right track by replacing all the sines. You'll have to use one of the double angle identities to get cos (2theta) in there.