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[Timothy.Siu]

Q10a. 5ln5 -4

b) i) a proof
ii)x=L/root2
iii) MP?=S(root2-1)

 

[fryziesutton]

series = 50, 60, 72...

a = 50 r = 1.2

the 8th zoom is the 9th term.

tn = ar^(n-1)

t9 = 50 x 1.2^8

= 214.99 mm = 215mm

ii)tn = ar^(n-1) = >400

50 x r^x = 400 ..... x = n-1

r^x = 8
1.2 ^ x = 8

log(1.2)8 = x

x = log 8
/log1.2

= 11.40

therefore it will be on the 12th zoom

 

[fryziesutton]

simpsons rule answer is 493 1/3

 

[janaranaran!]

Question FIVE:

c) i) 6000
ii) 0.2986
iii) 298.6 lux/m

oops i think i got 5 c) iii) wrong... to get the rate of change I derived and got
dI/dk = -s x I

and when s = 6, I= 1000, so my rate of change was decreasing 6000 lux/m

what did i do wrong?

 

[m.incognito]

Question 6:

 

[Timothy.Siu]

oops i think i got 5 c) iii) wrong... to get the rate of change I derived and got
dI/dk = -s x I

and when s = 6, I= 1000, so my rate of change was decreasing 6000 lux/m

what did i do wrong?

I=/=1000
I=Ae^-kt
i dont know exactly wat u did wrong...

 

[emo-kid-91]

oops i think i got 5 c) iii) wrong... to get the rate of change I derived and got
dI/dk = -s x I

and when s = 6, I= 1000, so my rate of change was decreasing 6000 lux/m

what did i do wrong?

you had to derive the whole formula after subbing in A and k.

 

[Wingom]

oops i think i got 5 c) iii) wrong... to get the rate of change I derived and got
dI/dk = -s x I

and when s = 6, I= 1000, so my rate of change was decreasing 6000 lux/m

what did i do wrong?

well you're supposed to get.. dI/ds (because it asks for lux/m)
and dI/ds = -kI

= -1/6ln6*1000 = -298.6 (as many ppl have said..)
So.. then i guess you put it is decreasing at 298.6 lux/m

 

[squeenie]

Question 6:

Awesome. Looks like I got it right then.

 

[m.incognito]

Questions 7 - 10:

 

[Rubes08]

4c
i) (x-h)^2= 4a(y-k)
(x-0)^2= 4a(y-3)
therefore vertext (0,3)
ii) a=2 so focus (0,5)

sketch blah blah
iv) area argh. so find the x points so like when they intercept. can't remember them then integrate. i changed it so that y was the subject of equation.
I can't remember what i did for iv

 

[Timothy.Siu]

Questions 7 - 10:

thanks i left early so they didn't let us take them

 

[squeenie]

thanks i left early so they didn't let us take them

I stayed through the entire exam, and I still couldn't get my paper!

 

[janaranaran!]

well you're supposed to get.. dI/ds (because it asks for lux/m)
and dI/ds = -kI

= -1/6ln6*1000 = -298.6 (as many ppl have said..)
So.. then i guess you put it is decreasing at 298.6 lux/m

oooh i see, I did dI/dk instead of dI/ds, what with the k being the constant and such.
should still get 1/2 hopefully

 

[YoungToby182]

Guys.....WHO CARES! Its over - there isnt A SINGLE THING you can do right now.

Just forget about it and move on, and wait to see what ur results are.

Just wasting time, when you need to focus on the next approaching exam

 

[Mongoz]

someone plZ show how u got 7a and 7c

 

[JamesTockuss]

What did people get for 6(c) ?

 

[minijumbuk]

What did people get for 6(c) ?

75pi/4 u³

 

[JimmyJimJim]

quoting from elsewhere...

Question 4 b)
50 x 1.2 = 60 (first application)
60 x 1.2 = 72 (second application)
72 x 1.2 = 86.4 (third)
86.4 x 1.2 = 103.68 (fourth)
103.68 x 1.2 = 124.416 (fifth)
124.416 x 1.2 = 149.2992 (sixth)
149.2992 x 1.2 = 179.159 (seventh)
179.159 x 1.2 = 214.49 (eighth)

continuing on...

214.49 x 1.2 = 257 (ninth)
257 x 1.2 = 308.86 (tenth)
308 x 1.2 = 370 (eleventh)
370 x 1.2 = 444 (twelfth)

This isn't correct, or at least it doesn't comply with what I have written on my exam paper, did they round off too early or are those mis-labled. I have:

1. 50
2. 60
3. 72
4. 86.4
5. 103.68
6. 124.416
7. 149.2992
8. 179.15904
9. 214.990848
10. 257.9890176
11. 309.5868211
12. 371.5041853
13. 445.8050224

You cannot do a half-zoom, therefore, it had to be 13.

 

[ozmadman]

Exam answers are up on www.pasthsc.com.au