c3 25th January 2013 exam

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8b was the bloody 9500= ln question where you had to do ln but cuz e was to two diffrnt powers that was only question that messed me up altho i think i culda got like 1 or 2 marks out of the 4 that it was

Yeah i never came across that before. I thought about using logs but good thing i didn't

Reply 141

Boss_sa

Original post by Lis slander

I found this one difficult [sin(22.5)+cos(22.5)]^2... but recollected how to do it as soon as I left the xam... :frown:

i was stressed out on that question too until it's 5 mins before the end and i figured out how to do it, did it on time! pheww!

Reply 142

Lis slander

ohhh yeah... I left the last part out.. but I think it would b sumthing lyk... -0.25=-1/4, -0.5=-1/2
1/4=(1/2)^2.... if u take the minus sign out.. and then factorise..

Reply 143

Putch1

Did anyone get £593? If not, i'm screwed

Reply 144

Nia_Beth

Original post by Sharqawi

I really liked the paper, until question 8b. Sat there for like 15-20 minutes trying to figure out how the hell to do it -- you couldn't ln (17000e^-0.25t - 2000e^-0.5t +500)
So I tried to seperate the terms and on both sides. But apparently you were supposed to create a quadratic.... Damn

Reply 145

Nia_Beth

Original post by Putch1

Did anyone get £593? If not, i'm screwed

Got that

.... I think -_-

Reply 146

Boss_sa

Original post by Lis slander

which ones???

the one where you have to answer T in the exact number form and the other one was the differentiation using quotient rule, i could do it but i'm not sure if i left it in the simplest form. what're we suppose to get?

Reply 147

Sharqawi

Original post by Putch1

Did anyone get £593? If not, i'm screwed

593 for what?

Reply 148

Putch1

Original post by Sharqawi

593 for what?

Rate of decreasing, last question

Reply 149

Cosectant

I found that paper quite challenging, definitely harder than most years, but I don't think it was the hardest paper. For question 8b, did anyone get ln16?

Reply 150

A*'s

Original post by Sharqawi

the thing i liked about this paper is that it required intense thinking and manipulation

Yup...
Everything was fine for me
The only things that puzzled me was finding the maximum question 7 I think it was
I worked it out but want to know what you guys got

I did 4 \ (I think it was) 2 + 10

10 being The value of R that I found.

And q 8b
I definitely got 1 or 2 marks through the first half of my working but couldn't finish it off because the base of e was different (although thinking of it now I think I should have factorised)

For (sin22.5+ cos22.5)^2
I got 1+ sin45 :biggrin:

Which gave me the answer (but apparently I had to simplify some more, so 1 mark lost there probably.

The five marker RANGE I got 0<= y< root 5/5

Urm.... Anything else ?

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Reply 151

A*'s

Original post by Putch1

Did anyone get £593? If not, i'm screwed

Yea rate of decrease was £593

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Reply 152

Nia_Beth

Original post by Putch1

Quadratic eh? Don't think so

My friend supposedly say that's how you do it, but I barely believe him - how to you do it - I'm trying it now cus that was the only part I couldn't do!!! I'm so obsessed with knowing how to do it

Reply 153

Riley F.

For 8b), you needed to form a quadratic. You had e^-0.5t and e^-0.25t, so you needed to turn the former into e^(-0.25t)2. Then with e^-0.25t = x, you could have x^2+x... and solve for t that way. I got an answer, plugged it in and got 9500 exactly.

Anyhow, the paper was ok, nothing more nothing less. However, I reckon silly mistakes may cost me in the end.

Reply 154

Nia_Beth

What grades are people aiming for/wanting to get after that exam?

Reply 155

A*'s

The first question was bizarre

W couldn't equal to 2.5, therefore w=0.5

B)
The tangent gradient was 160

(In the exam the numbers looked huge to me but apparently it's correct and the y=mx+c that I found made sense ... (To me))

I substituted w=0.5

In original equation to find y
(Y was a negative number, therefore I did)

Y+y1=160(x-0.5)

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Reply 156

SuziieB

Lol, look at us insomniacs...

My friend said for 8c that you were supposed to divide £593 by 8? Because it was 8 years? I don't think so though...I left mine as 593.

8b was to form a quadratic. I plugged ky answer in and got 9500 exactly.

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Reply 157

A*'s

Original post by Nia_Beth

What grades are people aiming for/wanting to get after that exam?

A

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Reply 158

SuziieB

For the range question was 0 part of the range or it was less than? And was root 5/5 part of the range or it was less than?

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