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Edexcel A2 C3 Mathematics 12th June 2015

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Reply 1620

rohan9777

If you have a fraction, can you divide every term in that fraction by the same thing?

Reply 1621

TheAnnabelle

Original post by frozo123

complete the square.

Omg thanks! I was scratching my head ahah

Reply 1622

Jimmy_M

Can we only use exact values for sin/cos30 and sin/cos45, or can we use 60 too?

Reply 1623

TheAnnabelle

Guys, do you have any tips about domain/range?

i ALWAYS seem to struggle to get those 2/3 marks

Reply 1624

frozo123

Original post by TheAnnabelle

Omg thanks! I was scratching my head ahah

Reply 1625

imedico10

Original post by Nirm

Can anyone tell me if this is correct or not?
So say the angle is 30 degrees and you found that out using arcsin.
And if question asked to find values from -180<x<180
(Using the CAST/Quadrant method)
Would the solutions/values be : 30,150,-30,-150?

its only 30 and 150

Reply 1626

username1042689

Original post by adorablegirl1202

I need help with c3 jan 2007 7d

-find the gradient from the equation they've given you
-differentiate f(x)
-set that equal to the gradient

Reply 1627

ridirahman

Original post by Humbers

You cant really find the domain from a graph in this case, you'd need to know to use common sense that ln(x+2) x+2 cannot be zero as ln0 is undefined

why is the answer 4>= y ? I thought y>=4.. I'm so confused

https://3fbd0e46fbbe11b4c200b26409e88de416eb0e39.googledrive.com/host/0B1ZiqBksUHNYOVhNT3cxSXp5WnM/Edexcel-Set-2/Ch.2%20Functions%20Qs.pdf

Reply 1628

User1686961

Original post by Gome44

Do these http://www.madasmaths.com/archive_iygb_practice_papers_c3_practice_papers.html

Had a look at these. Kinda useless.

Reply 1629

jake963

Original post by Pineappleheadish

Which year and month has the hardest C3 paper please

June 2013 probably https://07a69ccf283966549a9350d1a66951a7bc96e2dc.googledrive.com/host/0B1ZiqBksUHNYZ0JQM1NRcmdHdXM/June%202013%20QP%20-%20C3%20Edexcel.pdf

Reply 1630

username1042689

Original post by TheAnnabelle

Guys, do you have any tips about domain/range?

i ALWAYS seem to struggle to get those 2/3 marks

e^x > 0. Remember that as a stock one. And e^x^2 >= 1.
If you can, use a graph for reference.
If it's some kind of fraction, there may well be two limits (e.g. 1 < f(x) < 4). You can probably find the first limit by setting equal to 0 and the second one by just increasing x and seeing what it tends to.

Reply 1631

Graph

Original post by Jimmy_M

Can we only use exact values for sin/cos30 and sin/cos45, or can we use 60 too?

We can use 60 too. What makes you think we couldn't?

Reply 1632

ridirahman

Original post by TheAnnabelle

Guys, do you have any tips about domain/range?

i ALWAYS seem to struggle to get those 2/3 marks

same here

Reply 1633

Jimmy_M

Original post by Graph

We can use 60 too. What makes you think we couldn't?

I assumed so, especially considering sin30 = cos60.. Some revision notes I read said 30 and 45, didn't mention 60.. Thank you! :smile:

Reply 1634

math42

If a question firsts asks for you to state a harmonic form with the alpha or whatever it is rounded, am I still then okay to instead use the exact value of alpha for the rest of the questions, as they never seem to say "using your answer to (a)" or whatever so I'd otherwise feel at risk of getting some answers slightly wrong because of the rounding...