The way to do this is to write out the summations in full. I've attached a hand-written worked version if you're interested. BUT this "proof" has never come up in the exam. My recommendation when studying CT5 is... Read through the course notes as quickly as you can, keeping a high level view of all the theoretical material. Then start practising questions (any questions, but especially exam questions) as soon as you possibly can. Proofs rarely make up more than 5 marks in the exam - ie don't get bogged down in the theory. You don't need to be able to get from every line to the next line in order to pass. So if you don't even bother to look at the attached and just move on, the chance of this affecting your ability to pass is almost nil. But if you spend too long on the theory and not enough time on past questions this will affect your chances hugely. Use your study time wisely!
Just an add on here, I failed to get my exemptions in university is because I have study too much proofs and did not practice much exam and application questions. I am telling this from experience, and this time's exam I will not make the same mistakes again when studying!
Thank-you for your reply and the solution. Is there any proof in the 1st 4 chapter that is important for the exam point of view?
Not really. Don't worry about it. Lots of what's in the first 4 chapters is used to build up the rest of the course - ie these are some of the basic building blocks. At this stage you need to build up your understanding of the course and the best way is to (a) answer questions and (b) crack on with the next part of the study material. And take wzlee12's advice! Good luck!
