Core 3 Maths help

http://filestore.aqa.org.uk/subjects/AQA-MPC3-W-QP-JAN11.PDF
I just don't understand how to solve it
8bii and 8biii

For part b(ii) ...

let y=0 therefore...

$4e^{-2x} - e^{-4x} = 0$

$4e^{-2x} = e^{-4x}$

Then take the natural log to both sides...
$ln(4e^{-2x}) = ln(e^{-4x})$

Use the addition rule of logs to separate out the LHS...
$ln(4) + ln(e^{-2x}) = ln(e^{-4x})$

Use the log power rule to bring the exponent out the front and cancel out the ln e to give...
$ln(4) - 2x = -4x$

$2x = -ln(4)$

$x = - \frac{1}{2} ln(4)$

yaayyy philip top the rescue

damn you are quickeer than me

how you doing haha?

Haha

Not bad thanks, haven't seen your name crop up on a thread since we were preparing for our C1 and C2 resits

How's things going on your end?

my name cropping where haha? y
yea had S1 yesterday and physics unit 2

preparing for chem 1 AND m1
How about you?

Oh, how did S1 go? You're on Edexcel right? I heard quite a few people struggled with it!

Yeah still trying to perfect C3 and C4, it's not going too well though! Still struggling with a few things

yeaa Edexcel ..it was a hard paper

@Shadowfire123 Wow, I help OP by spending a long time writing everything in LaTex form and all I get is a lazy thumbs up back.

YOU'RE WELCOME!

*Takes note of name*

God, I'm glad I didn't bother resitting it otherwise I would have done worse than I did the first time! I'm quite content with being 3 marks off an A for that module

@Shadowfire123 Wow, I help OP by spending a long time writing everything in LaTex form and all I get is a lazy thumbs up back.

YOU'RE WELCOME!

*Takes note of name*

Teke note of the name?? meaning the boss is savage haha just given you a few rep for helping
do you want himto get you a coffee?
how did you write in La tex form

...

http://filestore.aqa.org.uk/subjects/AQA-MPC3-W-QP-JAN11.PDF
I just don't understand how to solve it
8bii and 8biii

What about biii)

I actually worked out the answer to part biii) on a bit of paper but then I didn't get a reply from OP so I thought they managed to figure it out considering similar log principles apply and I assumed that they know how to work out stationary points in general cases.

How are your university exams going btw?

Good so far! Three more to go on Probability Theory + Statistics, Group Theory and Number Theory but I suspect them to be alright.

I actually worked out the answer to part biii) on a bit of paper but then I didn't get a reply from OP so I thought they managed to figure it out considering similar log principles apply and I assumed that they know how to work out stationary points in general cases.


How are your university exams going btw?




@theboss1738 do you still need help with part biii) or have you managed to work it out?

Good so far! Three more to go on Probability Theory + Statistics, Group Theory and Number Theory but I suspect them to be alright.

Haha.
Yuck I hate coffee

LaTex takes a while to learn. There is a page on TSR that tells you everything you need to know but you slowly learn how to do it by yourself.

It's basically the same method isn't it?