Easy Question 10 or Easiest? (2 Viewers)

[ondroo]

Woot question 10 was (relatively) easy! Thank god it wasn't a complex geometry proof (only easy one )...

I got 4-5ln5 for a)

But for i) i think i missed a line in working but hopefully they wont penalise me.

I got l/√2 too for ii) and they same thing as my friends for iii which i forget :S

Argh i thought q9 c) stumped me more than q10 . I got i) fine but ii) i kinda got all confused and integrated properly but somehow found b and got 27 or something :S which noone got.

Yayyyy at least i got to check q1-6 tho so i'm hoping for 115+

 

[Kalashnikov47]

It was easy~~~LOL~~~easier than I expected~~~

 

[o0-Prodigy-0o]

for r 10A i made y the subject and found the unshaded area and minused it by the area of the triangle, to get the shaded area. i think it's right.

for 10B i proved the trianlges were similar, and then used the corresponding sides are equal to rule to find the top side for the top triangle.. subed them in together and got the answer. For (II) just simply proved the x-value was a minimum, etc... and part (iii) subbed in the x-value for the value of MP... and i fink i got it...

maybe lol not sure though lol:wave:

but yer i dunno if it was the easiest but it was alright

 

[lightning9t]

Woot question 10 was (relatively) easy! Thank god it wasn't a complex geometry proof (only easy one )...

I got 4-5ln5 for a)

But for i) i think i missed a line in working but hopefully they wont penalise me.

I got l/√2 too for ii) and they same thing as my friends for iii which i forget :S

Argh i thought q9 c) stumped me more than q10 . I got i) fine but ii) i kinda got all confused and integrated properly but somehow found b and got 27 or something :S which noone got.

Yayyyy at least i got to check q1-6 tho so i'm hoping for 115+

Sorry to put your hopes down, but 10.a) is 5ln5 - 4,

How did u guys justify 10.b) i drew a graph

 

[tybermon j]

FUCKING..... i forgot to minus that square.............. DAmnit..................................!!!!!!!!!!!!
Im jumping off a cliff now

 

[echeng]

ummm i finished 1-9 within 1.5 hour~ went bak to check over and left 30 minutes for Q10~ b) was easy i finished it all! but a) kinda got me =.= i think at about 5 minutes till pens down, i figured it out tat its a inverse trig kinda question! so i wrote A=7ln5-[e^y +2y] (with the boundaries 1n5 and 0)but i did not hav time to finish the last step ! wat can i possibly get? a 3/5?

 

[ondroo]

Sorry to put your hopes down, but 10.a) is 5ln5 - 4

Wait... i just redid it and yeah i did get that... so its all good

 

[lightning9t]

How did people justify 10.b) I just wanna see the different methods
I drew a graph with (x = a, and y = A) and drew a minimum graph with the stationary point (x = l/square root (2)), and proved that for values increasing between (l/square root(2) < x < l), A is increasing larger than when x = l/square root(2)...

Any other methods?

 

[ondroo]

How did people justify 10.b) I just wanna see the different methods
I drew a graph with (x = a, and y = A) and drew a minimum graph with the stationary point (x = l/square root (2)), and proved that for values increasing between (l/square root(2) < x < l), A is increasing larger than when x = l/square root(2)...

Any other methods?

2nd derivative, subbed in and since L is obviously positive then the second derivative had to be +tive therefore concave up therefore minimum.

 

[dodgyv]

回复: Easy Question 10 or Easiest?

MOTHERFCKERRR 10a WAS PISS EASY I COULDNT CHANGE LOG(X-2) and make X the SUBJECT ARGHHHHHHHHHHHHHHHHHHHHHHHHHHH SO ANGRY WORTH fUCKING 5 MARKS>....I didnt have time 2 look at 10b...actually i did write something...

i used area of ABsinC to get the first one and then...the other one i just left it Time was Up

 

[o0-Prodigy-0o]

2nd derivative, subbed in and since L is obviously positive then the second derivative had to be +tive therefore concave up therefore minimum.

yaya true true

 

[anurag1.2005]

um for 10b) II i just showed the first dirivitive.... would i get any marks fr dat???

n for 10c) i used a rmdon answer and subsituted dat to get a answer .... would dat be right???

 

[sasha279]

10 was strangely easy this year...

For b you had to sub MP as s(l-x)/x, since MPO and JKO are similar.
Then sub that into the 1/2a.b.sinC, then factor out s and sina.

Differentiate - solve for x then sub value into MP

I did that but my answer for part (ii) didn't look like theirs? It was very different and I spend pages and pages trying to factorise it, but it never matched...

I said the total area is

A = 1/2.s.x.sina + 1/2.(l-x).s(l-x)/x

and I think I'll get some marks for that but... I just couldn't factor it... It was so strange...

Ok, and for all you people worrying about part (a):

The way you solve it (since you can't integrate log functions) is you find the area of the whole rectangle (base x height), then you minus the integral of x = e^y (with limits on the y-axis this time), just like if you were finding the area between a curve and the y-axis.

I also didn't get the very last part (part (iii)?) of question 9. Totally stumped. Where is the beam when x = 0?! I went round and round in circles...

Other than that, checked all my answers, pretty confident. I'm happy to post up any solutions if you can remember the questions ^_^ anyone know when we'll see the papers up? Or not before next year?

Sasha

 

[Felix Jones]

omg...i got all the questions except that stupid mother f$%# easy one where ur supposed to find volume...i totaly forgot bout u-sunstitution....istnt that 3-unit method??
anyways hope i do well...gotta study for 3-unit on wednesday...i'm scared.

i found 10 easy btw...got all of them.

 

[Timothy.Siu]

yeah question 10 was really easy, 10a) was a joke, easy 5 marks and 10b) was more of a question 9 question

 

[sasha279]

omg...i got all the questions except that stupid mother f$%# easy one where ur supposed to find volume...i totaly forgot bout u-sunstitution....istnt that 3-unit method??
anyways hope i do well...gotta study for 3-unit on wednesday...i'm scared.

i found 10 easy btw...got all of them.

V = pi x integral(x^2dy or y^2dx)

 

[Felix Jones]

V = pi x integral(x^2dy or y^2dx)

i know!! 'cry'.
i dont know what was wrong wif me then...'sigh'.

 

[sasha279]

i know!! 'cry'.
i dont know what was wrong wif me then...'sigh'.

Hehe, one of my friends forgot to put proofs in the geometry question! That's a bit of a worry hey

 

[munchiecrunchie]

probably the easiest question 10 i've ever seen.

 

[henry08]

I didn't get 10 b.