Edexcel Core 3 - 21st June 2016 AM

Thanks 😊 Im not sure if this is clear enough, not used to working with arcsin etc :


Posted from TSR Mobile

4/4 marks (I wonder what that thing is in the background though )

By the way, as my offers post exams are always missed amongst the flood of posts, if anyone somehow would have access to this paper (same goes for C4, probs don't remember most remaining applied modules well enough though) on the day I'd be happy to do solutions. Not exactly necessary because probs Zacken and kprime will have some done soon after as well but me being a no-life I'm sure with access to the paper I could have things down fairly soon after the exam lol.

For FP2, Zacken had to wait 24 hours to get access to the paper, IDK about kprime. So if you are able to get access to the papers before the 24 hours then anyone on the forum would be extremely happy and eternally grateful, but I'm doubting you'll be able to.

Fair enough, I wouldn't expect it. I'll be back home by then, maybe I can nip to my old school for one..

Yep. Zacken and Kprime get it 24 hours after the exam. You could ask them whether or not you could do one of the papers, certainly would be interesting!

Yep. Zacken and Kprime get it 24 hours after the exam. You could ask them whether or not you could do one of the papers, certainly would be interesting!

f(x) = k
So f(x) - k = 0
K transforms f(x) by shifting it down by k units. We need to find the value of k which will mean f(x) will intersect with the x axis in two places. In the graph I've attached, if k is 1, the graph will have one root, meaning that as long as k > 1, the function will have two roots.
Another poster said you could do it using the discriminant, and you could, but this is how you would do it if you don't actually have f(x), and you just have a graph as some questions I've seen. I'll try and find an example and edit this post.

Posted from TSR Mobile

Ohh now i get it. thanks so much! so if it asks for when k has one root. then thats k=1. If it asks for when k has no roots then k< 1. is that correct?

Not simultaneously - try applying them both to the original to the equation, one at a time.

I managed to do it but I'm not sure if my method makes sense...

So since arcsinx = arccosy, I said

Sin[arccosy] = x
and
Cos[arcsinx] = y

Then I said

Sin[arcsinx] = x
and
Cos[arcsinx] = y

Using the identity sin²x + cos²x = 1,

Sin²[arcsinx] + Cos²[arcsinx] = 1

Therefore it follows that:

x² + y² = 1.

Would I still get the marks for this? I guess I kinda did what you guys did but in a roundabout kind of way xD

Not generally speaking, no, that only applies to the graph I've posted. The idea though applies to any curve. You're just looking for the translation which will cause the curve to intersect with the x axis in two places. I'll get another graph, see if you can apply that idea to another curve entirely.

Posted from TSR Mobile

My Year 13 maths teacher was pretty relaxed, I'm sure if I just go in unannounced and ask for a C3 paper I can get one...

Dont teachers need to wait 24 hours before they can get it too?

Do we have to know any proofs for this module ?


Posted from TSR Mobile

I dunno. Either way, I was never actually gonna do that..
Although actually I think I recall I was having a dispute after the FP1 exam with someone because she and I got different answers and seemed to remember the question being slightly different and we went like thirty minutes after the exam and were able to look at a paper.

https://b3755649dbd1afe3db91a899c3b9837b22326254.googledrive.com/host/0B1ZiqBksUHNYMG14YWtobVJUUms/for-Edexcel/Solomon%20K%20QP%20-%20C3%20Edexcel.pdf

Can someone help me with q2b here. Im not getting the right answer when I do long division and I dont quite understand what the mark scheme does
Thanks