2 Unit Revising Marathon (4 Viewers)

[nightweaver066]

Re: 2 Unit Revising Marathon HSC '10

A tiny bit of a mistake there nightweaver. Check it again.

Thanks for that.

 

[MrBrightside]

Re: 2 Unit Revising Marathon HSC '10

HAHA e^0 is not zero newbs.

it's 1

 

[MrBrightside]

Re: 2 Unit Revising Marathon HSC '10

would you lose marks for using the quadratic formula, not showing the factorisation?

I think you do for a question that specifically says Factorise this equation ...

But not for when your working out stationary points.

 

[powlmao]

Re: 2 Unit Revising Marathon HSC '10

would you lose marks for using the quadratic formula, not showing the factorisation?

I think you do for a question that specifically says Factorise this equation ...

But not for when your working out stationary points.

You don't lose marks unless the question says you must use this method.

The questions I have seen in the past papers never say you must use certain methods.

 

[MrBrightside]

Re: 2 Unit Revising Marathon HSC '10

My school is only up to functions! (We have done barely anything)

Other than that I just know most of Trig, intergration, differeniation and probability

Are you in Year 11?

 

[powlmao]

Re: 2 Unit Revising Marathon HSC '10

Are you in Year 11?

Yeah I am in year 11.

But I wanna finish the Whole 2U course by the end of this year.

 

[SpiralFlex]

Re: 2 Unit Revising Marathon HSC '10

Anyone going to attempt nightweaver's question or do I have to do it? I'll be back to do it after I do my English essay. [Hint: Differentiate to find velocity equation and differentiate again to find acceleration equation.]

 

[powlmao]

Re: 2 Unit Revising Marathon HSC '10

Anyone going to attempt nightweaver's question or do I have to do it?

Can you repost it.

 

[SpiralFlex]

Re: 2 Unit Revising Marathon HSC '10

Scroll up. I am off to do an essay that is due tomorrow.

 

[powlmao]

Re: 2 Unit Revising Marathon HSC '10

Soz Found it.

 

[powlmao]

Re: 2 Unit Revising Marathon HSC '10

You mean y-axis? If there are limits on the y-axis, then you should be rotating about y-axis. Anyways..



Volume of bounded region rotated about y-axis:




Question:

1.

x=2sin2t

sub 0

x=2sin

2. dx/dt= 2sin2t
= (grr not sure

then you d2x/d2y and that is it

3. sub 0 into the d2x/d2y

4 Not sure.

Anyone want to check I believe I have the idea of how to get it but I believe it is wrong.

Anways, i need to work on my trignometric differeniation.

 

[SpiralFlex]

Re: 2 Unit Revising Marathon HSC '10

1.

x=2sin2t

sub 0

x=2sin

2. dx/dt= 2sin2t
= (grr not sure

then you d2x/d2y and that is it

3. sub 0 into the d2x/d2y

4 Not sure.

Anyone want to check I believe I have the idea of how to get it but I believe it is wrong.

Anways, i need to work on my trignometric differeniation.

Almost there. Work on your trigonometric differentiation skills, the first derivative of a displacement equation is the velocity equation and the derivative of that is the acceleration equation. Think what it actually means by initial velocity. What is time equal to?

 

[JennaJameson]

Re: 2 Unit Revising Marathon HSC '10

i found dis pr3tty intredasting

A haz mass 2m, B haz mass m, whole thing is rotated at constant angular velocity w, other deets r in teh diagram br8s

find teh tension in OA and OB

gogogogogo faggots

 

[powlmao]

Re: 2 Unit Revising Marathon HSC '10

Almost there. Work on your trigonometric differentiation skills, the first derivative of a displacement equation is the velocity equation and the derivative of that is the acceleration equation. Think what it actually means by initial velocity. What is time equal to?

Thanks

I am happy that I can get sort of close to the answer.

 

[Hermes1]

Re: 2 Unit Revising Marathon HSC '10

Do this question:

In an arithmetic progression of 49 terms, the middle term is 13. Find the sum of all terms.

 

[nightweaver066]

Re: 2 Unit Revising Marathon HSC '10

Do this question:

In an arithmetic progression of 49 terms, the middle term is 13. Find the sum of all terms.

Since the arithmetic progression is of 49 terms, the middle term must be the 25th term.

So, T(25) = 13 = a + (25-1)d
13 = a + 24d

Now, sum of all terms is:
S(49) = 49/2 (2a + 48d)
= 49(a + 24d)

Subbing in the first equation:
S(49) = 49 x 13
= 637

New question or wait til the other person finishes the question?

 

[Hermes1]

Re: 2 Unit Revising Marathon HSC '10

Since the arithmetic progression is of 49 terms, the middle term must be the 25th term.

So, T(25) = 13 = a + (25-1)d
13 = a + 24d

Now, sum of all terms is:
S(49) = 49/2 (2a + 48d)
= 49(a + 24d)

Subbing in the first equation:
S(49) = 49 x 13
= 637

New question or wait til the other person finishes the question?

i dont understand do u want me to post another question?

 

[nightweaver066]

Re: 2 Unit Revising Marathon HSC '10

i dont understand do u want me to post another question?

Powlmao didn't finish posting his solution to the question. You can post another question if you like to keep me entertained.

 

[Hermes1]

Re: 2 Unit Revising Marathon HSC '10

A man is entitled to an annual payment which, for each year, reduces by one-eighth of the previous year. If the first payment is $800, show that however long he may live, he will not receive more than $6400 altogether

If x, y, z form an arithmetic progression and the reciprocals of y, z and w also form an arithmetic progression show that yz = xw

 

[hscishard]

Limiting sum

Use a-d, a and a+d
Then use 1/a, 1/(a+d) , 2/(a+d) - 1/a
Show LHS =RHS