Application of Complex Numbers question (1 Viewer)

[ajtho777]

Hi y'all, I'm a little stuck on this particular question. I am unable to do part an and b. I've derive the identity by expansion and was wondering if there was another way to do so. Question two required the derivation of tan(4theta) and the initial parts of that question use the derivation of sin(4theta) and cos(4theta). If extra info is required please mention it because I feel like I've forgotten to mention something...

 

[ivanradoszyce]

This may help. The PDF was written using Latex.

 

[ajtho777]

Thank you, ivanradoszyce.

 

[ajtho777]

Hi again, I'm unable to prove the roots in part b. Could someone help?

 

[liamkk112]

View attachment 42957
Hi again, I'm unable to prove the roots in part b. Could someone help?

View attachment 42957
Hi again, I'm unable to prove the roots in part b. Could someone help?

multiply the equation by cos theta , you can then use the identity from part a

 

[ivanradoszyce]

Here is part a) and b) written in Latex. I'll post part c) soon. For c) use Vieta's formula. Attached are full solutions + a file about Vieta's formula for cubics.