Year 12s: what will be the first way you research your future options? >>

This discussion is now closed.

Check out other Related discussions

Edexcel A2 C3 Mathematics 12th June 2015

Scroll to see replies

Reply 1460

adorablegirl1202

Original post by Gilo98

Have you got f(0) yet?

I decided to come up with an equation of the line using c1 stuff and got y - 10 = -10/4 (x + 2) and from that got f(0)=5 bit confused now

Reply 1461

Maham88

Original post by physicsmaths

I have noticed this year, M3 similar style to IAL, FP2 similar style to IAL not difficulty, physics today was also similar style to IAL.

Posted from TSR Mobile

for the jan 2015 one ?

Reply 1462

Gilo98

Original post by adorablegirl1202

I decided to come up with an equation of the line using c1 stuff and got y - 10 = -10/4 (x + 2) and from that got f(0)=5 bit confused now

it is five. but look below at the conventional approach using similar triangles. Apply a similar method for f(5) on the RHS branch.

13_June_C3_UK_Model_red-2_pdf__page_10_of_13_.png49.4KB

Reply 1463

shuff_joe

Original post by Gilo98

Can someone explain why the answer to June 2013 8b is 21/25 and not -21/25? If you see the equation as 21/25sec(x-73.74) then surely the min is negative??

Sec = 1/cos()
Therefore the larger cos is, the smaller sec is, so the minimum is when cos is at its maximum, which is 1

Posted from TSR Mobile

Reply 1464

randlemcmurphy

Original post by Gilo98

Can someone explain why the answer to June 2013 8b is 21/25 and not -21/25? If you see the equation as 21/25sec(x-73.74) then surely the min is negative??

Speed is a scalar quantity.

Reply 1465

Gilo98

Original post by shuff_joe

Sec = 1/cos()
Therefore the larger cos is, the smaller sec is, so the minimum is when cos is at its maximum, which is 1

Posted from TSR Mobile

I get that, but when you look at a sketch of secx, it goes below the x axis so how can the minimum be +ve?

Reply 1466

Gilo98

Original post by randlemcmurphy

Speed is a scalar quantity.

Thought this would be the reason why, thank you

Reply 1467

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?

(edited 8 years ago)

Reply 1468

moment of truth

Original post by callyx27

So how's everyone feeling about tomorrow?

Quite good, although am still worried because I need to get like 90+UMS. What about you? :smile:

Reply 1469

TheAnnabelle

Is "proof by counter example" part of the spec? Is there a reason it crops up in the Soloman papers? It really makes me panic!

Posted from TSR Mobile

Reply 1470

Nurishment

Can someone explain how to do b) ? I thought because x was 0 you'd use 5-2(5-2(0)) = -5 but the model answer and mark scheme both say the answer is e^2 - 4. Help ?

Reply 1471

imedico10

which solomon papers do you guys recommend doing?

Reply 1472

TheAnnabelle

Also, sorry to bug, is it 90 ums in each paper? Or 90 ums average against both papers?

Posted from TSR Mobile

Reply 1473

imedico10

Original post by Nurishment

Can someone explain how to do b) ? I thought because x was 0 you'd use 5-2(5-2(0)) = -5 but the model answer and mark scheme both say the answer is e^2 - 4. Help ?

which paper is this?

Reply 1474

Nirm

Original post by TheAnnabelle

Also, sorry to bug, is it 90 ums in each paper? Or 90 ums average against both papers?

Posted from TSR Mobile

90 UMS average against both papers i think

Reply 1475

shuff_joe

Original post by Gilo98

I get that, but when you look at a sketch of secx, it goes below the x axis so how can the minimum be +ve?

You have to consider it as 1/cos not sec on its own, I understand your confusion but the sec graph has an indeterminable minimum y value

So treat sec as 1/cos
25/21×(1/cosx) (or whatever the fraction was)

Cos needs to be it's maximum for 1/cos to be the minimum, so cos(x) = 1

25/21 × (1/1)

25/21

I apologise if I got the fraction wrong, on phone and forgot what it was :P

Posted from TSR Mobile

Reply 1476

adorablegirl1202

Original post by Gilo98

it is five. but look below at the conventional approach using similar triangles. Apply a similar method for f(5) on the RHS branch.

Thanks, I can do this now! :smile:

Reply 1477

imedico10

Original post by Nurishment

Can someone explain how to do b) ? I thought because x was 0 you'd use 5-2(5-2(0)) = -5 but the model answer and mark scheme both say the answer is e^2 - 4. Help ?