banner_jpg
Username/Email: Password:
Forums

Homework Help

Pages (26) [ 1 2 3 4 5 6 Last ] Next
You must be registered to post!
From User
Message Body
Post #332448 - Reply to (#331611) by Noobsrus
user avatar
The last Blood Elf
Member

7:30 am, Nov 4 2009
Posts: 200


Quote from Noobsrus
( i j k )
( 2 -3 -1 )
( x y z )
If you find the determinants you end up with

i(-3z - y) - j(2z - x) + k(2y + 3x)
....
There is an infinite number of solution so I'm really confused about the question now... lol
....

You are solving simultaneous equations ( a middle school problem) using matrix O_O and
do it wrong from the beginning O__O
plus, you are trying to find a nonexistent vector O____O

And the solution above is okay, not really pretty though:
f(x) = ax+b
inv f(x) = bx+a
The definition of inverse function: f(inv(f(x)) = x for every value of x
thus a(bx+a)+b = x or (ab-1)x + b +a^2 = 0 for every value of x
---> ab-1=0 and b+a^2=0 ----> a=b=-1

________________
User Posted Image
Post #332547 - Reply to (#332443) by qwert123
user avatar
Tea Leaf
Member

2:37 pm, Nov 4 2009
Posts: 192


Quote from qwert123
f(x)=ax+b
to find f^-1(x):
y = ax+b
x = ay+b
y = (x-b)/a
f^-1(x) = (x-b)/a
but : f^-1(x) = bx+a
so
x/a = bx and -b/a = a
b = 1/a and b = -a²
1/a = -a²
a(1/a) = a(-a²)
1 = -a³

a = -1
b = 1/-1 = -1
------
a + b = -2


thanks! i forgot i could do that...but splitting them into two other equations never crossed my mind... ^_^;


________________
The river of life is magnificent and dangerous.
user avatar
Mishy
Member

2:43 pm, Nov 4 2009
Posts: 1737


does anyone know how to do decipher a kind of matrix code?

________________
Nulla in mundo pax sincera
"Always go too far, because that's where you'll find the truth." - Albert Camus
Post #332618 - Reply to (#332550) by chineserider
user avatar
Member

7:16 pm, Nov 4 2009
Posts: 510


Quote from chineserider
does anyone know how to do decipher a kind of matrix code?

be more specific?


user avatar
Rebel Rebel
Member

12:01 pm, Dec 14 2009
Posts: 1230


Can someone super smart when it comes to Physics possibly pm me? I'm practically begging anyone. I've got some problems, that I need explained. I'm not looking for specific answers as I have them, but I need the concept explained to me, so that my incapable brain can comprehend -_-

Thanks in advance (to anyone willing to help).

Post #341995
user avatar
Site Admin

12:39 pm, Dec 14 2009
Posts: 2275


Could you give an example; so, we can see the problems level of difficulty. I can understand basic physics... but the application of calculus in physics I have not done.

________________
"Officially, this machine doesn't exist, you didn't get it from me,
and I don't know you. Make sure it doesn't leave the building."
user avatar
Wall-o-text
Member

5:03 pm, Dec 14 2009
Posts: 367


Posting here would probably be better Akane, more input the better.

________________
Do not feed the trolls
User Posted Image
Post #342063 - Reply to (#341995) by Toto
user avatar
Member

7:37 pm, Dec 14 2009
Posts: 510


Quote from Toto
but the application of calculus in physics I have not done.

I'm tutoring calc based E&M, so I could possibly help with that. Seconding toto and noobsrus that you should just post, 'cause there are lots of science and engineering people floating around this board who may not consider themselves good enough in physics to PM you but may give great explanations to some of your questions.

Post #342065 - Reply to (#342063) by story645
user avatar
Member

7:42 pm, Dec 14 2009
Posts: 1668

Warn: Banned



Quote from story645
Quote from Toto
but the application of calculus in physics I have not done.

I'm tutoring calc based E&M, so I could possibly help with that. Seconding toto and noobsrus that you should just post, 'cause there are lots of science and engineering people floating around this board who may not consider themselves good enough in physics to PM you but may give great explanations to some of your questions.



Engineering totally pwns any field of science!! eek

________________
Gay book discussion thread
Quote from you_no_see_me_
this is not about cannibalism...please get back on topic

Quote from Toto
I think it is exactly the topic. I see nothing wrong.
Post #342066 - Reply to (#342065) by BoxBox
user avatar
The last Blood Elf
Member

7:50 pm, Dec 14 2009
Posts: 200


Quote from BoxBox
Quote from story645
Quote from Toto
but the application of calculus in physics I have not done.

I'm tutoring calc based E&M, so I could possibly help with that. Seconding toto and noobsrus that you should just post, 'cause there are lots of science and engineering people floating around this board who may not consider themselves good enough in physics to PM you but may give great explanations to some of your questions.



Engineering totally pwns any field of science!! eek

How about Physics & applied Physics ? eek
I m studying engineering and always feel attached to physical and mathematical science laugh i chose my major kind of randomly.

________________
User Posted Image
user avatar
Rebel Rebel
Member

7:53 pm, Dec 14 2009
Posts: 1230


Ok, ok. Let me gather my thoughts/info and post them later. There are several reasons I didn't and one is embarrassment >_<, as they seem simple enough. Another is that, this is something I'm turning in as a make-up exam, so I was afraid of disclosing too much info as I fear judiciary reviews (yeah, paranoid much?). I'll go through and make them as generic as I can. It's general college physics so I'm sure you can all understand it except for me laugh. Thanks for the replies c:

Post #342070 - Reply to (#342067) by MasamiAkane
user avatar
Member

8:33 pm, Dec 14 2009
Posts: 510


Quote from MasamiAkane
one is embarrassment >_<, as they seem simple enough.

We all had to learn this stuff once and most of us were quite puzzled with it, especially the stuff that seems really simple now.

Quote
. Another is that, this is something I'm turning in as a make-up exam, so I was afraid of disclosing too much info as I fear judiciary reviews (yeah, paranoid much?)

As long as you're allowed to research stuff and we're not solving the problems for you, it should be fine.

Post #342087 - Reply to (#342067) by MasamiAkane
user avatar
Member

9:57 pm, Dec 14 2009
Posts: 1668

Warn: Banned



Quote from MasamiAkane
Ok, ok. Let me gather my thoughts/info and post them later. There are several reasons I didn't and one is embarrassment >_<, as they seem simple enough. Another is that, this is something I'm turning in as a make-up exam, so I was afraid of disclosing too much info as I fear judiciary reviews (yeah, paranoid much?). I'll go through and make them as generic as I can. It's general college physics so I'm sure you can all understand it except for me laugh . Thanks for the replies c:



ummm....usually colleges monitors the websites your visit and monitors the chat system as well. So chances are they know what you are doing but just don't care enough to do anything.... eek


Quote from story645
Quote from MasamiAkane
one is embarrassment >_<, as they seem simple enough.

We all had to learn this stuff once and most of us were quite puzzled with it, especially the stuff that seems really simple now.

Quote
. Another is that, this is something I'm turning in as a make-up exam, so I was afraid of disclosing too much info as I fear judiciary reviews (yeah, paranoid much?)

As long as you're allowed to research stuff and we're not solving the problems for you, it should be fine.

The answer is obviously 42, dughhhh embarrassed

________________
Gay book discussion thread
Quote from you_no_see_me_
this is not about cannibalism...please get back on topic

Quote from Toto
I think it is exactly the topic. I see nothing wrong.
user avatar
Rebel Rebel
Member

5:14 pm, Dec 15 2009
Posts: 1230


A person with a mass of M and a volume of V floats on the water. What is the volume of the person above the water?

When an upward force is applied, the volume of the person above the water is increased by X. What is F?

That's all the info I'm given (I'm assuming the density of the water is 1000 kg/m^3). I know that this has something to do with Archimedes' Principle and buoyancy. The question specifically ask the volume of the person above the water, which really confuses me, unless I'm over thinking this.

Post #342268 - Reply to (#342266) by MasamiAkane
user avatar
Wall-o-text
Member

5:21 pm, Dec 15 2009
Posts: 367


Quote from MasamiAkane
A person with a mass of M and a volume of V floats on the water. What is the volume of the person above the water?

When an upward force is applied, the volume of the person above the water is increased by X. What is F?

That's all the info I'm given (I'm assuming the density of the water is 1000 kg/m^3). I know that this has something to do with Archimedes' Principle and buoyancy. The question specifically ask the volume of the person above the water, which really confuses me, unless I'm over thinking this.


For something to float in water it has to have a density less than 1000kg/m3.
So if density is mass/volume and you know the mass then you can find out the volume of the person

When you say what is F, I assume you're talking about the upward force.
The boyancy force F is
Quote
F = pgV - mg

, where p is the density, g acceleration due to gravity, V is volume, and m is the mass. If you want to know how to derive this equation you can PM me.

Some references
Buoyancy
• The upward force (buoyancy)
acting on a body immersed in a
fluid is equal to the weight of an
equivalent volume of the fluid.

Edit: Sorry I'm abit too lazy to tackle the question, even-though I should be able to do it on the fly since I'm studying buoyancy in fluid statics lol. Just going to give you the theory XD. I too get a feeling I'm over-thinking this, are all the values M V X or F not given? I'm feeling so inadequate right now lol.

Last edited by Noobsrus at 5:36 pm, Dec 15 2009

________________
Do not feed the trolls
User Posted Image
Pages (26) [ 1 2 3 4 5 6 Last ] Next
You must be registered to post!