Can anyone please guide/help me with this question, i have attached it to the post,
thank you.
The equation looks so complicated, I just dont know where to even begin?
It looks like you did not properly substitute.
When you properly substitute there is a lot that disappears because it's zero.
Btw, you could have simplified the fraction with in it - it's just 1.
No need to do that now though, because you first need the proper substution.
Furthermore, if you can't reasonably simplify, that's fine. It means you are done and that you have the answer.