proofs for edexcel maths

hi guys, can someone tell me the proofs we need to know for c1, c2 and s1, c3, c4 and s2?

thank you ;D

anybody?

hi guys, can someone tell me the proofs we need to know for c1, c2 and s1, c3, c4 and s2?

thank you ;D

I think also the sine and cosine rules and I'm not too sure about the quadratic equation one.

Proof by inspection (work every possibility out).
The equating of two trig with a three lined equal sign between them is a type of proof too.
The reasons for F(x) = 1

I was going to write brute force!
Trig identities proof yes but there can also be anything they ask you so get from point A to point B. Well you need to understand that $sumF(x)=1$ because that's all there can be.

I recommend you post a specific example since $sumF(x)=1$ is very confusing and it's hard to know what you're trying to say,

The sum of all the probabilities in a given set where the amount of events does not change is equal to one. This can include the probability that the events do not happen which is an event on its own.

So

$EXiPi=1$

Ah you're talking about probability - you really should have mentioned this since "The reasons for F(x) = 1" could have meant anything

No, it does not mean only one thing. (for example, it can be an antiderivative, one of a few functions like the Dawson function, etc.) There is more to mathematics than examinations (I've seen you apply the attitude that "the exam board or 'my textbook' says this, so it's true"

hi guys, can someone tell me the proofs we need to know for c1, c2 and s1, c3, c4 and s2?

thank you ;D