Homework help topic

[heartless101 83]

1st of all, thank you so much for creating this thread VenRox Now I won't have to be so confused with my homework

 

Alright so anyways, so I'm taking USA History right now. So, my group got assigned the colony of Georgia and the group elected me to be the "Governor" of the state which means that I will have to create a promotional flyer to others convincing people to settle there and I will also have to act as the "official greeter" for the colony for the "settlement fair". Also, I will have to answer questions about Georgia.

 

So this is my question, what would be one "factoid" about Georgia that would convince people to settle in Georgia?

[SuperPunk 13]

The fertile land that produces many crops of pecans, peanuts, and peaches.

I guess that would be one.

 

Mmmm, peaches.

[heartless101 83]

Thanks I can finally start to get working on my poster "advertisment flyer" for Georgia

[Vanitas 127]

i need help with finding ratio and rates in general

i dont understand it

[SuperPunk 13]

Ratios are basically fractions.

 

Say if you have 3/5, it turns to 3:5.

 

I don't know about rates. I haven't had math like that since middle school so I might be wrong.

[RoxAs Is Wise 7]

Aren't rates basically percentages?

[the15thwiseone 1]

 

I am sorry i forgot it was 4b not 2 b....i was just used to...giving that as an example...

 

Ignore that part...lol i misstyped 2 alot

 

/facedesk.

 

@butterflylexi: i hope you said 1

 

o-o;

Uh, no, "1" is the wrong answer.

Not sure how you got that.

It's a trick question. The answer was that there was no answer.

/mymathteacherhatesmeeee

 

So amber is bare foot? I think the proper answer in that case would be "not enough information"

 

@Aaron: I solved it: it goes like this...

 

Take the cone, and transform it into a triangle with a rectangle inside: Much like as if you took a Cross sectional area of the intersectional point...

 

Next you want to appoint variables to the spots that arn't given a value such taht:

2-r=x and...5-h=y....

 

This is where it gets a little tricky...if you notice ther are 2 pairs of triangles in this situation there are...2 x*h/2 trianges (area of that triangle) and there are also 2 r*y/2 triangles...multiply both by two you get

x*h+r*y

 

The total area of this large triangle without the rectangle is 2*5/2 (per right triangle) multiplied then by 2. This results in 10 cm^2.

 

Next there is an equation you can write:

10-x*h(1st triangle pair)-y*r(second triangle pair)=2*h*r(the area of the rectangle)

 

Whew: almost there!

Next replace x and y with thier equivelants...

10-2h-5r+2h*r=2h*r

take the 2h*r over to the right side...and you get...

10-2h-5r=0 (an extremely good sign)

get h isolated on the left side...

h=(5r-10)/-2

negative 1 change:

h=(10-5r)/2 that is the equation...

[Aaron 579]

Lol are you 100% sure thats right

http://www.wolframalpha.com/input/?i=(10-5r)/(2-r)

Nice try, but it cancels out to 5?

 

pretty sure the answer is

 

h = 5(1-r/2)

[the15thwiseone 1]

Lol are you 100% sure thats right

http://www.wolframalpha.com/input/?i=(10-5r)/(2-r)

Nice try, but it cancels out to 5?

 

pretty sure the answer is

 

h = 5(1-r/2)

 

I fixed it: i figured out i forgot to multiply the recangle of r*h by 2...

[FireStorm 162 23]

Daniel and I had our one of our final maths exams yesterday. This was the last question on the paper. Bet noone can do it. Daniel thinks he got it right. But i didn't...

 

http://www.facebook.com/photo.php?fbid=103928033011372&set=a.103928029678039.5310.103926663011509

 

I can't believe i actually get this...... but my brain still hurts from figuring this out and trying to make it sound smart as well, evil Cone of Death

 

Ok, so you have to use similar triangles to do this, i think it was taught in year 9 or 10, and after that it was considered general knowledge, so it wasn't re-taught, unless you were in "General Mathematics" (Standard maths in NSW, basically the lowest level)

 

So similar triangles means that if, for example there is a cone inside another cone, then, the radius over the height for the first cone would equal the same as the radius divided by the height of the second cone (put simply r/h = a/b, where r = radius of first cone, h = height of first cone, a = radius of second cone and b = height of second cone) It can also be shown the other way around, so that it makes h/r = b/a, where the letters are the same.

 

Okay, is everyone confused yet, because here comes the longer part, where we have to think *waits for people to start dying from confusion*

 

So, if the height of the height of the cylinder is h, and the height of the bigger cone is 5, then the height of the smaller cone is the size of the bigger cone minus the cylinder height, so it's 5 - h. Now the radius of the cylinder is 2, and so is the smaller cone, since they fit together and all

 

5 - h/ 2 = 5 / 2

 

Now, this means that h = 5 (1 - r/2) and that's the answer

 

I think that's right, but it might be wrong

 

Sorry about double posting, but this is about my homework problems, and the last post is already big enough, so yeah....

 

OK, here is my evil maths work (my teacher said this is the easy work of the start of my HSC, so i'm gonna die );

 

A rain water tank is to be designed in the shape of a cylinder with radius r and height h metres.

 

The volume of the tank is to be 10 cubic metres. Let A be the surface area of the tank, including it's top and base, in square metres.

 

(When i say n, it means pi, but writing the word pi is too confusing)

 

part 1. Given that A = 2nr^2 + 2nrh, show that A = 2nr^2 + 20/r

 

part 2. Show that A has a minimum value and find the value of r for which the minimum occurs.

 

I need a LOT of help with this, coz i'm confused....

[the15thwiseone 1]

Sorry about double posting, but this is about my homework problems, and the last post is already big enough, so yeah....

 

OK, here is my evil maths work (my teacher said this is the easy work of the start of my HSC, so i'm gonna die );

 

A rain water tank is to be designed in the shape of a cylinder with radius r and height h metres.

 

The volume of the tank is to be 10 cubic metres. Let A be the surface area of the tank, including it's top and base, in square metres.

 

(When i say n, it means pi, but writing the word pi is too confusing)

 

part 1. Given that A = 2nr^2 + 2nrh, show that A + 2nr^2 + 20/r

 

part 2. Show that A has a minimum value and find the value of r for which the minimum occurs.

 

I need a LOT of help with this, coz i'm confused....

 

show that A+2nr^2+20/r????....what are you showing? ...is ther supposed to be a equal sign?

[FireStorm 162 23]

 

Sorry about double posting, but this is about my homework problems, and the last post is already big enough, so yeah....

 

OK, here is my evil maths work (my teacher said this is the easy work of the start of my HSC, so i'm gonna die );

 

A rain water tank is to be designed in the shape of a cylinder with radius r and height h metres.

 

The volume of the tank is to be 10 cubic metres. Let A be the surface area of the tank, including it's top and base, in square metres.

 

(When i say n, it means pi, but writing the word pi is too confusing)

 

part 1. Given that A = 2nr^2 + 2nrh, show that A + 2nr^2 + 20/r

 

part 2. Show that A has a minimum value and find the value of r for which the minimum occurs.

 

I need a LOT of help with this, coz i'm confused....

 

show that A+2nr^2+20/r????....what are you showing? ...is ther supposed to be a equal sign?

 

Sorry, the + sign after the last A was meant to be an = sign, i guess i just forgot to take my finger off the Shift button lol, i'll fix that up

[the15thwiseone 1]

I'll take a look at it and get it back to ya in a few: ya just want a general guide to which direction ya need to go? or ya want a step by step.

[FireStorm 162 23]

Step by Step please, i'm confused on everything to do with hard maths, but i want to learn how to do the maths so i can get a high mark for the HSC this year, so i need to learn how to do this from start to finish

[the15thwiseone 1]

Part A i just finished:

Given: A=2nr^2+2nrh prove that A=2nr^2+20/r...

 

Using the fact that the volume is 10m^3....and the volume formula being:

 

nr^2h=V that means we can solve for...the equation as : either:

a. h=blah

b. r=blah

 

well: we will be h=blah because r is still inside of the second part of the Area equation.

 

so given that V=10... the equation for volume becomes:

 

nr^2h=10

Next we isolate h on the left side:

h=10/(nr^2)

 

we plug in this value for h into the Area formula:

 

A=2nr^2+(2nr10)/(nr^2)

 

We simplify that term by the n's cancel, 1 r cancels ontop with a bottum, and it becomes...:

A=2nr^2+20/r

 

The first part finished answer above ^^^^^^;

 

Second part below VVVVVVVVV;

So in this one you replace the value of 10 of V, with just plain V: you plug it into the last equation we had so that it becomes:

A=2nr^2+2*V/r....

 

Next you must take the derivative of the whole equation in respect to r...thus leading to:

dA/dr=d(2nr^2)/dr+d(2*V/r)/dr...

 

which makes: A'=4nr-2*V/r^2

If you set A' to 0 you will get... this:

0=4nr-2*V/r^2

 

Pull 2*V/r^2 to the left side:

2*V/r^2=4nr

Multiply by r^2 on both sides:

2*V=4nr^3

replace V with the Volume equation:

2*nr^2h=4nr^3

devide by 2nr^2 on both sides:

h=2r

 

This signifies the minimum value for any given a with this fix volume.

 

Final answer for part two above ^^^^^^^;

I hope this helped.

[FireStorm 162 23]

Cool, this helped a lot, thanks

[sneezes 73]

Guys, stop double posting. This is like the fifth time I have to delete double posts. Geez.

[Noctis007 0]

Hi jenflo....i heard you needed help in chemistry? i'll be happy to help ^.^

[the15thwiseone 1]

1. List the Aufbau sequence of orbitals from 1s to 7p.

 

2. Write the electron configuration for the following. (No short cuts).

a. Kr

b. W

c. Fe

 

3. What elements are represented by the following configurations? Ground or excited?

a. 1s^2 2s^2 2p^5

b. 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^8

c. 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^9

d. 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^10 5p^6 6s^2 5d^1

e. [Ar]4s^2

f. [Xe]6s^2 4f^4

 

I seriously do not understand this Chemistry shit. & I thought the whole Mole thing was hard...

 

This has to do with...the electron configuration of an atom...

so the example 3 part a has to deal with an atom that has 4+5 9 electrons....where b has to deal with 4+6+2+6+2+9+8=37 electrons...

 

All of those part 3 deal with the electrons and you can just use the periodic chart to find how much electrons.

 

Part 2 is different...you want to find how many electrons the atom has based on the periodic chart, and use the method you would use to fill in the "spots" properly much like the style you see in part 3.

 

Part 1 you do this:

 

1s^2 2s^2 2p^6 3s^2 3p^6 4p^8 4s^2 4p^6 .....etc. untill you get to 7p.

[sneezes 73]

This has to do with...the electron configuration of an atom...

so the example 3 part a has to deal with an atom that has 4+5 9 electrons....where b has to deal with 4+6+2+6+2+9+8=37 electrons...

 

All of those part 3 deal with the electrons and you can just use the periodic chart to find how much electrons.

 

Part 2 is different...you want to find how many electrons the atom has based on the periodic chart, and use the method you would use to fill in the "spots" properly much like the style you see in part 3.

 

Part 1 you do this:

 

1s^2 2s^2 2p^6 3s^2 3p^6 4p^8 4s^2 4p^6 .....etc. untill you get to 7p.

 

That doesn't...really...make sense. Lol.

 

What you're explaining to me is something totally & completely different than from what my Chemistry teacher (attempted) explaining to me.

 

Basically, I didn't understand a thing you said. Sorry.

[the15thwiseone 1]

I do not understand how you Don't understand what i said...

 

I'm telling you everything my chemistry teacher is teaching me...and that i know is how you figure out the solutions to the problems.

 

I do not see how this is so difficult to grasp.

 

Perhaps the reason why you are having a difficult time with this: is because your teacher is teaching it in a difficult manner, or not presenting things clear.

[sneezes 73]

I do not understand how you Don't understand what i said...

 

I'm telling you everything my chemistry teacher is teaching me...and that i know is how you figure out the solutions to the problems.

 

I do not see how this is so difficult to grasp.

 

Perhaps the reason why you are having a difficult time with this: is because your teacher is teaching it in a difficult manner, or not presenting things clear.

 

Yeah, probably. Thanks anyway for trying to help me. I appreciate it : )

[Noctis007 0]

i believe for number 1 its:1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

[the15thwiseone 1]

i believe for number 1 its:1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

 

Yes, i agree with you and believe that is correct.

[DragonMaster 1,166]

Hi, guys I have problem that I don't get. It is Algebra I. Here it is:

 

The area of a circle with a radius r is given by the formula A=pi[r]^2 Use this fact to find a formula for the shade are in the figure below.

This is the best I could do to replicate the image.

 

I know that my final answer should be A=pi[r](w)+pi(w)^2 but my teacher will kill me if I don't show my work. I am utterly lost on this. It is probably simple and I am just over complicating it, but any help would be appreciated.

 

*the "r"'s are in brackets because they make these ® with parenthesis, just pretend the brackets are parenthesis.*