2 Unit Revising Marathon (2 Viewers)

[MrBrightside]

Re: 2 Unit Revising Marathon HSC '10

The correct way is:

(i) 1 sock is chosen out of 8 socks. Therefore are four pairs, therefore only 1 more sock out of the 7 will give a matching pair to the sock initially chosen.

therefore P(Sock does not match) = 6/7

(ii)* After selecting the third sock:

8/8 * 6/7 * 4/6

P(No matching pair after third sock) = 4/7

(iii)* P(First three matching pair) = 1 - 4/7

=3/7


*Explanation is confusing for parts ii and iii. If someone can explain this it would be most helpful.

 

[asianese]

Re: 2 Unit Revising Marathon HSC '10

The correct way is:

(i) 1 sock is chosen out of 8 socks. Therefore are four pairs, therefore only 1 more sock out of the 7 will give a matching pair to the sock initially chosen.

therefore P(Sock does not match) = 6/7

(ii)* After selecting the third sock:

8/8 * 6/7 * 4/6

P(No matching pair after third sock) = 4/7

(iii)* P(First three matching pair) = 1 - 4/7

=3/7


*Explanation is confusing for parts ii and iii. If someone can explain this it would be most helpful.

Oh....for ii) its like you've picked 1, then there are 6/7 left, but from the remaining you can only choose 4 because if you had 5 to choose from you would get a pair from the 2nd sock?? (please be right...)

and for iii) its the complementary so yep?

 

[MrBrightside]

Re: 2 Unit Revising Marathon HSC '10

Oh....for ii) its like you've picked 1, then there are 6/7 left, but from the remaining you can only choose 4 because if you had 5 to choose from you would get a pair from the 2nd sock?? (please be right...)

and for iii) its the complementary so yep?

Yeah ii is right I think. I was going to say that but, I couldn't get it down exactly. So pretty much there's 8 socks. first draw he picks one. therefore 7 left. 2nd draw he can only pick one more sock that will satisfy the match. after 3rd draw, He only has 4 to choose from, because the other would be for the second sock. therefore giving the 4 / 6 socks on 3rd draw.

iii yeah complementary event, is it saying that the possibility of getting a correct match to the first sock drawn after the third sock is 3/7?

 

[asianese]

Re: 2 Unit Revising Marathon HSC '10

Differentiate:


Hence show that:

 

[nightweaver066]

Re: 2 Unit Revising Marathon HSC '10

Differentiate:


Hence show that:

Am i the only one who finds this question invalid..?

I'm guessing you missed the limits.

 

[powlmao]

Re: 2 Unit Revising Marathon HSC '10

Am i the only one who finds this question invalid..?

I'm guessing you missed the limits.

How do you those questions?? My school is so slow and I can do everything besides the intergration and hard part of intergration

 

[sandnigger]

Re: 2 Unit Revising Marathon HSC '10

How do you those questions?? My school is so slow and I can do everything besides the intergration and hard part of intergration

u r shit!

 

[powlmao]

Re: 2 Unit Revising Marathon HSC '10

u r shit!

How about you fuck off and study for you Arts course.

 

[sandnigger]

Re: 2 Unit Revising Marathon HSC '10

How about you fuck off and study for you Arts course.

lol dickhead, I am everyones favourite maths tutor .

I do engineering/commerce and I rip maths up.

 

[powlmao]

Re: 2 Unit Revising Marathon HSC '10

lol dickhead, I am everyones favourite maths tutor .

I do engineering/commerce and I rip maths up.

Sure you do.

 

[nightweaver066]

Re: 2 Unit Revising Marathon HSC '10

How do you those questions?? My school is so slow and I can do everything besides the intergration and hard part of intergration

You would do need to differentiate first:
y = (x-1)(ln2x) (i'm assuming it's a log to the base e)
y' = (x-1)/x + ln2x

Now you want to integrate ln2x

Lets just rearrange what we just differentiated.
y' = 1 - 1/x + ln2x
ln2x = 1/x - 1 + y'

Sub that in to

And now it should be easy to integrate.

 

[powlmao]

Re: 2 Unit Revising Marathon HSC '10

You would do need to differentiate first:
y = (x-1)(ln2x) (i'm assuming it's a log to the base e)
y' = (x-1)/x + ln2x

Now you want to integrate ln2x

Lets just rearrange what we just differentiated.
y' = 1 - 1/x + ln2x
ln2x = 1/x - 1 + y'

Sub that in to

And now it should be easy to integrate.

haha sounds great.

I just haven't done log, so when I do that it should make it alot easier

 

[sandnigger]

Re: 2 Unit Revising Marathon HSC '10

haha sounds great.

I just haven't done log, so when I do that it should make it alot easier

ur going to fail , you haven't even finished the course yet.

The hsc is in like 6weeks or something aye?

Shoudl have got a tutor fail XD

 

[powlmao]

Re: 2 Unit Revising Marathon HSC '10

ur going to fail , you haven't even finished the course yet.

The hsc is in like 6weeks or something aye?

Shoudl have got a tutor fail XD

Yeah, awkies since I am in year 11 and have finished everything besides log.

 

[SpiralFlex]

Re: 2 Unit Revising Marathon HSC '10

Here's a great minimum question.

is a point on the curve and is a point on the curve with the same coordinate as

Determine the value of that gives a minimum distance

 

[powlmao]

Re: 2 Unit Revising Marathon HSC '10

Here's a great minimum question.

is a point on the curve and is a point on the curve with the same coordinate as

Determine the value of that gives a minimum distance

How would you solve this??

I would be lazy and draw a diagram, get the coordinates and use the distance formula.

 

[SpiralFlex]

Re: 2 Unit Revising Marathon HSC '10

How would you solve this??

I would be lazy and draw a diagram, get the coordinates and use the distance formula.

Clue: You need to find the expression for the distance first.

 

[towelhead5]

Re: 2 Unit Revising Marathon HSC '10

Clue: You need to find the expression for the distance first.

lol bunch of dumbasses

 

[powlmao]

Re: 2 Unit Revising Marathon HSC '10

Square root of (x-x1)^2 + (y-y2)^2?

 

[towelhead5]

the distance is the sqrt of the difference of the functions, differentiate etc , easy as fuck