You are Here: Home >< Maths

# Edexcel A2 C3 Mathematics 12th June 2015 watch

1. (Original post by daniellj)
When were using ln(x) do we have to put ln|x| as in ln modulus of x because our maths teachers getting stressy saying we have to otherwise we lose marks
You won't lose marks, look at the mark schemes, they never have ln|x|
2. (Original post by Jonnyss)
When solving for x

eg. tanxcos2x=2cos2x
tanxcos2x-2cos2x=0

do u factorise cos2x out: cos2x(tanx−2)=0

or do you cancel cos2x out: tanx-2=0 to then get tanx=2

You factorise cos2x out leaving you with: cos2x(tanx-2)=0

Then you know that cos2x=0 and tanx-2=0
3. could someone please explain 4d?
https://07a69ccf283966549a9350d1a669...%20Edexcel.pdf
4. Can I ask for part b of this question why it isn't:

-(x-a) = 3x + 5a

For where the positive part of the graph meets the negative part help please Solomon paper L Q6)

Posted from TSR Mobile
5. Predictions for 90 ums tomorrow?
6. Could somebody please give me a quick rundown on finding the domain/range of a function?
7. Do i lose method mark if i do quotient rules and product rule in my head and skip let xxx=u let yyy=v du/dx=something dv/dx=something ??
8. What past papers do people think this exam will most likely resemble?? Anyone have any ideas?
9. What's the hardest paper? I've done all the Solomon and elmwood, but haven't really done any of the actually papers. Which years should I do?
10. try june 2013
11. (Original post by gregsey28)
What's the hardest paper? I've done all the Solomon and elmwood, but haven't really done any of the actually papers. Which years should I do?
Definitely June 13 and 14, probs the hardest of the normal papers
12. (Original post by gregsey28)
What's the hardest paper? I've done all the Solomon and elmwood, but haven't really done any of the actually papers. Which years should I do?
try june 2013 btw where are the elmwood paper?
13. (Original post by gregsey28)
What's the hardest paper? I've done all the Solomon and elmwood, but haven't really done any of the actually papers. Which years should I do?
June 2013 is by far the hardest, you only needed 57/75 for 90 UMS
https://07a69ccf283966549a9350d1a669...%20Edexcel.pdf
There is a diagram which shows f(x)=2|3-x|+5

You know if f(x)=k this would be a horizontal line intersecting the y-axis at k.
You've been told in the question that f(x)=k has exactly two roots, therefore f(x)=k must intersect f(x)=2|3-x|+5 twice.

From the diagram you can tell that a horizontal line which crosses f(x)=2|3-x|+5 twice must be greater than the minimum value (the bottom of the v shape) and must be less or equal to where f(x)=2|3-x|+5 crosses the y-axis. A horizontal line (f(x)=k) between these points would intersect twice therefore (f(x)=k) would have exactly two roots.

So you must find the minimum value and the value where it crosses the y-axis. then you know that k would be greater than the minimum but less than or equal to the value where it crosses the y-axis.

Hope this helps (its quite hard to explain but i've done my best to simplify it down).
15. Which is the hardest elmwood paper?
16. f(x) = 2[3-x]+5
at the root x=0 therefore f(0) ---> f(x) = 11
so k<= 11
since ---> f(x)=k ---> 2[3-x]+5=k
2[3-x]=k-5 so k>5
so 5<k<=11
17. Can someone explain to my why on C g(x^2) =ln2x^2 and g(x^3)=ln2x^3
18. (Original post by 1122ag)
There is a diagram which shows f(x)=2|3-x|+5

You know if f(x)=k this would be a horizontal line intersecting the y-axis at k.
You've been told in the question that f(x)=k has exactly two roots, therefore f(x)=k must intersect f(x)=2|3-x|+5 twice.

From the diagram you can tell that a horizontal line which crosses f(x)=2|3-x|+5 twice must be greater than the minimum value (the bottom of the v shape) and must be less or equal to where f(x)=2|3-x|+5 crosses the y-axis. A horizontal line (f(x)=k) between these points would intersect twice therefore (f(x)=k) would have exactly two roots.

So you must find the minimum value and the value where it crosses the y-axis. then you know that k would be greater than the minimum but less than or equal to the value where it crosses the y-axis.

Hope this helps (its quite hard to explain but i've done my best to simplify it down).
Ah thanks, i get it! I know that we would find the point it intersects the x axis by x = 0, how about the minimum point?
19. (Original post by xMystics)
Do i lose method mark if i do quotient rules and product rule in my head and skip let xxx=u let yyy=v du/dx=something dv/dx=something ??
If you get the answer right you won't lose any marks - but if the answer is wrong and the working isn't there the examiner won't be able to award you the marks for the working
20. Can someone tell me how to work out angles using cos? DO you add 360 or do 360 - PV?

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: June 21, 2016
Today on TSR

### Cambridge interviews

Find out who is getting invitations

### University open days

• Heriot-Watt University
School of Textiles and Design Undergraduate
Fri, 16 Nov '18
• University of Roehampton
Sat, 17 Nov '18
• Edge Hill University
Faculty of Health and Social Care Undergraduate
Sat, 17 Nov '18
Poll
Useful resources

Can you help? Study help unanswered threadsStudy Help rules and posting guidelinesLaTex guide for writing equations on TSR

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE