Official BOS Trial 2015 Thread (4 Viewers)

leehuan · Oct 4, 2015

Drsoccerball said:
Page 1 of question 16 was to prove AM-GM second was with trap rule lol...

Yeah. Exactly. Like, dot dot dot.

Side note cause I cbf opening my inbox astro continues after my sadness over English ends

Drsoccerball · Oct 4, 2015

leehuan said:
Yeah. Exactly. Like, dot dot dot.

Side note cause I cbf opening my inbox astro continues after my sadness over English ends

After 13th of October?
Btw how do you think i knew carrot already uploaded the file to dropbox?

leehuan · Oct 4, 2015

Drsoccerball said:
After 13th of October?
Btw how do you think i knew carrot already uploaded the file to dropbox?

Yeah. I've been looking at a band 4 for English for at least 3/4 of this year. I'm finally raising my hopes again of getting a band 5 so I really want to focus my studying on English now.

It's easy to study maths-physics-chemistry. Just do 2 past papers a day swapping subjects per day. It's not like I have any exams between English and maths.
_____
Idk...

Librah · Oct 4, 2015

Few peeps gotta improve their exam technique, legit i saw someone hold their calculator without writing anything for like 30 minutes straight in the exam.

Drsoccerball · Oct 4, 2015

Drsoccerball · Oct 4, 2015

Librah said:
Few peeps gotta improve their exam technique, legit i saw someone hold their calculator without writing anything for like 30 minutes straight in the exam.

Was that me :L? I don't even remember i was just out of it

leehuan · Oct 4, 2015

Librah said:
Few peeps gotta improve their exam technique, legit i saw someone hold their calculator without writing anything for like 30 minutes straight in the exam.

That is concerning. I'm glad that's not me. Besides, honestly how many 4U questions these days use a calculator

Librah · Oct 4, 2015

Drsoccerball said:
Was that me :L? I don't even remember i was just out of it

I don't think so, but the guy who i think was Gabriel Moussa looked completely lost during the 3u lmao.

Ekman · Oct 4, 2015

Librah said:
I don't think so, but the guy who i think was Gabriel Moussa looked completely lost during the 3u lmao.

That sounds like Gabriel Moussa, its most likely him

Drsoccerball · Oct 4, 2015

Librah said:
I don't think so, but the guy who i think was Gabriel Moussa looked completely lost during the 3u lmao.

hahahaha dying... He was the guy in white next to me... He asked me if he could copy my multiple choice... I should've let him considering i circled only one answer for nearly every question...

kawaiipotato · Oct 4, 2015

leehuan said:
That is concerning. I'm glad that's not me. Besides, honestly how many 4U questions these days use a calculator

Lol I use it for basic arithmetic. Can't trust myself with addition

leehuan · Oct 4, 2015

kawaiipotato said:
Lol I use it for basic arithmetic. Can't trust myself with addition

True, that may as well be important I guess. But then again that only takes 10 seconds. Unless you're in 2U and waste time on financial maths..

camdaman12 · Oct 4, 2015

from looking at everyones responses, think i got rekt harder than TSM

Mathsisfun15 · Oct 4, 2015

When do we get our marks?

Paradoxica · Oct 6, 2015

Mathsisfun15 said:
How did you fellas get the induction one?

I don't know how to do it by induction. Here is my mixed analytical approach.
$$Proposition$: n^{n+1} > {(n+1)}^n$ for all n $ \geq 3$
$Base case$: n=3, 3^4 > 4^3 \Leftrightarrow 81>64,$ which is true. So P(3) is true.$
$$Suppose P(k) is true. So $ k^{k+1} > {(k+1)}^k$
$P(k+1) = {k+1}^{k+2} > {(k+2)}^{k+1}$
$Take the log of both sides. This does not change the inequality, as each side is strictly positive for our set of values for k.$
$(k+2)\ln(k+1) > (k+1)\ln(k+2) \Leftrightarrow (k+2)\ln(k+1) - (k+1)\ln(k+2)>0$
$\Rightarrow (k+1)(\ln(\frac{k+1}{k+2})) + \ln(k+1) > 0 \Leftrightarrow \ln \left ( \left ( \frac{k+1}{k+2} \right )^{k+1} \right ) + \ln(k+1) > 0$
$Observe that $\ln \left ( \left (\frac{k+1}{k+2} \right )^{k+1} \right )$ is negative for all positive k. Taking the limit to infinity, the inside term approaches $ \frac{1}{e} $ from the definition of e. So the entire term approaches $ -1. $ The difference of two concave expressions is also concave. Since the function is strictly negative and concave, the inequality is strengthened to less than -1. Now consider the remaining term. $\log{(x+1)}$ is concave and grows without bound. By testing the case k = 3, we conclude that in all our possible values of k, the inequality is true. Therefore, k+1 is true.$

Drsoccerball · Oct 6, 2015

What my X2 teacher said about that induction question :
"Looks symmetrically beautiful or beautifully symmetrical.

"
Biggest troll

Trebla · Oct 6, 2015

Drsoccerball said:
What my X2 teacher said about that induction question :
"Looks symmetrically beautiful or beautifully symmetrical. "
Biggest troll

The Ext1 or Ext2 induction qn?

Drsoccerball · Oct 6, 2015

Trebla said:
The Ext1 or Ext2 induction qn?

The ex 1 induction question

Paradoxica · Oct 6, 2015

Any criticism or feedback on my attempt at the power inequality induction?

Drsoccerball · Oct 6, 2015

Paradoxica said:
Any criticism or feedback on my attempt at the power inequality induction?

1/3 since you didnt use induction...

Official BOS Trial 2015 Thread (4 Viewers)

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