Edexcel C3,C4 June 2013 Thread

Scroll to see replies

Original post by Theafricanlegend

why isnt it 3^-xln-3?

y = -3 ^ (-x)
ln y = - ln 3 ^-x
ln y = x ln 3
1/y dy/dx = ln 3
dy/dx = (-3 ^ (-x) * ln 3)

although it should be positive ....

Reply 5001

Supes180

How do you find the coords minimum/maximum of a curve? I know you differentiate and equate to 0, but how do you find one if there is a both a minimum and a maximum? If I remember correctly, it should come out with two results, and the negative one is the x coord of the maximum?

Reply 5002

nm786

Original post by Rayquaza

Still stuck :/

expand the brackets and if you sub it back into the original equation what do you get? it should be pretty straightforward now..

Reply 5003

F1's Finest

Original post by zzz.

alot of people are saying the c4 paper is gnna be worse than the C3 ppr!!! :frown:

But your comment made me happy.. What makes you think that though?? :smile:

I doubt the paper would be that hard, remember Edexcel would have listened to the recent criticism from the C3 paper.

It depends on when the C4 papers were delivered to the schools. If they were delivered a couple of days after the c3 exam, then it wouldn't be such a hard paper!

Remember to stay positive and do your best! That's the only thing you can do :yy:

Reply 5004

Jullith

Original post by kuku2013

hey thanks, I don't understand from the 5th step!! why do you have to make it all into ln(2)?

I turned it into ln2, so that I can factorise it out.

Reply 5005

MathsNerd1

Original post by ACBLISS

integration :wink:

Okay well I'd use the substitution of U = X^2 and that should then equate it down rather nicely :tongue:

Reply 5006

Theafricanlegend

integrate 1/sin^2xcos^2x please help

Reply 5007

Jullith

Going to head off now. Good luck for tomorrow everyone! :smile:

Reply 5008

hilo36

Original post by MathsNerd1

Just remain calm as if you've covered everything then that's all you can do, now getting a good nights rest before the exam would be very advisable by myself as you'll be both physically and mentally prepared :smile:

Thanks

Reply 5009

OneMorePanda

Original post by Kreayshawn

can someone tell me what shapes we need to know the area/volume of?
i've asked a few times but no response, don't wanna have to skip a whole question on the exam because i don't know the area/volume of something basic

This is largely off the top of my head, somebody correct me if I've missed anything. As you can see, most of them are very simple. The only tricky ones, I think, would be the volume of a cone (1/3 * base * height), and area of a regular shape (which will almost definitely not come up).

2D areas

•

Circle/semicircle

•

Rectangle

•

Triangle

•

Any regular shape (although they would have to give you a hint)

3D volumes

•

Sphere/hemisphere

•

Cuboid

•

Cone (for any base)

•

Prism (cylinder is the most likely one to be asked for)

3D surface areas

•

Cuboid

•

Err...

You are given these by the formulae booklet (in the C1 section)

•

Surface area of a sphere

•

Surface area of a cone

Reply 5010

Story

Can anyone confirm if we have to integrate x/1+x . = x-ln(x+1) ?

(edited 10 years ago)

Reply 5011

MathsNerd1

Original post by Story

Can anyone confirm if we have to integrate x/1+x . = x-ln(x+1)

This is what I got :smile:

Reply 5012

nm786

Original post by Theafricanlegend

integrate 1/sin^2xcos^2x please help

hint:

sin^2xcos^2x =( \frac{1}{2}sin2x )^2

Reply 5013

MedMed12

Is it just me or is June 12 really nice? Please please c4 paper, be like that D:

Reply 5014

MedMed12

Original post by MathsNerd1

Only on the questions that ask you to use substitution but I'm saying that I'll use the technique when trying to integrate the ones that can be done by recognition so I need to work out a suitable substitution first :tongue:

Ohh I see