# need to confirm some answers: (1 Viewer)

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#### gaoOO

##### Guest
What was the answer to the very last question, 7 b iv)
I got something very small like 0.16, and something larger.
I managed to finish the test with about 25 min remaining, and checked my whole paper except for 7 b)
So far nothing wrong i think

i can't believe i wrote down the ranges for the last question instead of the widths.

#### sting24

gaoOO said:
i used the definite integral approach.

probably on the family one i got 1/5, did anyone else get that?
yea it was (4! x 3!)/6! which is 1/5

#### fishy89sg

##### Member
1. did people get 1.1664 for their answer in Question 5 (a) (ii)?

2. did u guys get pi^2 / 12 for question 3 (a)

3. did u guys get pi/4 for question 1 (d)

4. is the answer to question 7 (b) (iv) really 1.28metres and 0.159metres? and (iii) 0.8 <= m <= 1.2 ??

G

#### gaoOO

##### Guest
fishy89sg said:
1. did people get 1.1664 for their answer in Question 5 (a) (ii)?

2. did u guys get pi^2 / 12 for question 3 (a)

3. did u guys get pi/4 for question 1 (d)

4. is the answer to question 7 (b) (iv) really 1.28metres and 0.159metres? and (iii) 0.8 <= m <= 1.2 ??

apart from the last question, 7 b)iv) i got all the same answers as you i think.

G

#### gaoOO

##### Guest
can someone explain why we take the positive case for the

ln (x + root blah) etc. question (inverse)

#### fishy89sg

##### Member
gaoOO said:
can someone explain why we take the positive case for the

ln (x + root blah) etc. question (inverse)
im assuming its somethin to do with part (i)

#### sting24

gaoOO said:
can someone explain why we take the positive case for the

ln (x + root blah) etc. question (inverse)
its + not negative because if its negative, then x + root(x^2 +4)/2 is negative, and this means that it would be f-1(x) = log (negative answer) which does not exist because logx can only be x>0, so its postive

#### missburwood

##### New Member
isnt question d ii a trick question?
when you find x dont you need to minus it from 2000 ?I thought the x indicates where you would be awhen t=10???

maybe i was tricked arrghhhhhhh not sure

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#### gaoOO

##### Guest
sting24 said:
its + not negative because if its negative, then x + root(x^2 +4)/2 is negative, and this means that it would be f-1(x) = log (negative answer) which does not exist because logx can only be x>0, so its postive
oh good, so it was ok for me to write

e^y > 0 therefore take positive case + etc.

#### Legham

##### Active Member
fishy said:
1. did people get 1.1664 for their answer in Question 5 (a) (ii)?

2. did u guys get pi^2 / 12 for question 3 (a)

3. did u guys get pi/4 for question 1 (d)

4. is the answer to question 7 (b) (iv) really 1.28metres and 0.159metres? and (iii) 0.8 <= m <= 1.2 ??

I didnt do the last one, but i had the same as you for the first 3.

miss burwood said:
isnt question d ii a trick question?
when you find x dont you need to minus it from 2000 ?I thought the x indicates where you would be awhen t=10???

maybe i was tricked arrghhhhhhh not sure
"Find the distance that she has fallen in the first ten seconds."

How far she has travelled, not where she has travelled to. You were tricked.

##### New Member
hey guys, how many solutions were there for 5(c) and what did people get for 6 (b)(iii), cheers.

#### fishy89sg

##### Member
OK,

1. so is the answer for question 2 (d) (ii) confirmed at 283m?

2. and are the answers for question 4 (a) (i) (ii) and (ii) confirmed at
0.01
0.285 and
0.43 respectively?

3. and how did you guys find the max value for h for question 7 (b) (ii)

4. for question 6 (a) (iv), were the 4 answers pi/4, 3pi/4, 5pi/12 and 7pi/12?

5. and final call for the confirmation of 7 (b) (iv) as
1.28metres and 0.159metres???? lol

thanks so much in assisting me calculate my estimate raw mark.

#### Hikari Clover

##### Member

fishy89sg said:
yeh i had 1.28metres and 0.159metres for the two distances....

i got them too:wave:

#### cc =)

##### New Member
missburwood said:
isnt question d ii a trick question?
when you find x dont you need to minus it from 2000 ?I thought the x indicates where you would be awhen t=10???

maybe i was tricked arrghhhhhhh not sure
yerrs that qn was tricky. It sounds right to minus 2000 from it and i forgot to do that =(

for qn 5 c, are there meant to be two values for each x and y ? or only one ?

grrs qn 7 >=/

#### Legham

##### Active Member
1. so is the answer for question 2 (d) (ii) confirmed at 283m?

2. and are the answers for question 4 (a) (i) (ii) and (ii) confirmed at
0.01
0.285 and
0.43 respectively?
Yeah. 99% sure.

G

#### gaoOO

##### Guest
fishy89sg said:
OK,

1. so is the answer for question 2 (d) (ii) confirmed at 283m?

2. and are the answers for question 4 (a) (i) (ii) and (ii) confirmed at
0.01
0.285 and
0.43 respectively?

3. and how did you guys find the max value for h for question 7 (b) (ii)

4. for question 6 (a) (iv), were the 4 answers pi/4, 3pi/4, 5pi/12 and 7pi/12?

5. and final call for the confirmation of 7 (b) (iv) as
1.28metres and 0.159metres???? lol

thanks so much in assisting me calculate my estimate raw mark.
1) it was 283. xx but i can't remember which way it rounded. i hope i didn't round wrong.

2) i'm pretty sure about those ones

3) 3 - 0.4h > 0 therefore h < 7.5

4) as mentioned, i got 11 pi/ 12 instead of 7pi /12

#### Hikari Clover

##### Member

Legham said:
Hmm.. well, gaa00 agrees with you, and someone in the general thoughts thread agreed with my answer We'll soon find out lol.

edit: actually, im pretty sure you're right. me and the other girl forgot to add a constant when integrating i think.

wait,i found that the constant is 0,i use t=0 and x= 0 as the initial condition

#### mrzeidan1

##### Tigers '08
fishy89sg said:
OK,

1. so is the answer for question 2 (d) (ii) confirmed at 283m?

2. and are the answers for question 4 (a) (i) (ii) and (ii) confirmed at
0.01
0.285 and
0.43 respectively?

3. and how did you guys find the max value for h for question 7 (b) (ii)

4. for question 6 (a) (iv), were the 4 answers pi/4, 3pi/4, 5pi/12 and 7pi/12?

5. and final call for the confirmation of 7 (b) (iv) as
1.28metres and 0.159metres???? lol

thanks so much in assisting me calculate my estimate raw mark.
agreed on all questions.

maximum value of h, i set the stuff in the square root = 0 and solved for h?

edit: had an 11pi/12 somewhere in there though, cant remember exactly

Last edited:

#### sting24

fishy89sg said:
4. for question 6 (a) (iv), were the 4 answers pi/4, 3pi/4, 5pi/12 and 7pi/12?
um i got all those exept 1pi/12, i think its 11pi/12

#### DJ99

##### New Member
I worked out the distance the skydiver fell to be 283 just then, but 533 seems so familiar. Hope I didn't accidentally write 533.

Probability of green eyes-
i) 0.01
ii)0.285
iii)0.323