#1

Anything relating to mathematical theory, demonstration, or application, including homework questions and whatnot, GOES IN HERE. There's way too many threads about this stuff >_<.

GOGOGOGOGOGOGO

GOGOGOGOGOGOGO

#2

What is 1/0?

OH SHI-

OH SHI-

#4

There's a math/science thread.

This thread is redundant.

Like the notes in between that keep throwing me off.

This thread is redundant.

Like the notes in between that keep throwing me off.

#5

limits suck i have ap calc this year and im not looking forward to it

#6

^Old. Try this

7+7=-2

7+7=-2

#7

Delete.

#9

I searched for a mathematics thread, nothing came up. Plus, having seen a thread within the last couple months reminds people to search for it when they have a question.

#10

^Old. Try this

7+7=-2

WHAAAAAAAAT!????!??!

#11

WHAAAAAAAAT!????!??!

Don't worry about it, only the elite may get this answer.

I didn't know this thread existed.. I asked a math homework question the other day in a completely new thread.

My apologies.

It was just created tonight.

#12

i dunno, but im taking calc 1 in the fall and i am going to need all the help i can get.

#13

My older brother is a math major. Fu

*cking nerd.*
#14

Demostrate Euclid's theorem

#15

^Old. Try this

7+7=-2

7+7= -2 mod8

#17

^Old. Try this

7+7=-2

*types in calculator*

*7+7=14*

Em..you appear to be mistaken.

...unless my calculator is broken

#18

Root -1 = -1^1/2 = ((-1)^2)^1/4 = 1^1/4 = 1

There you have it: root -1 = 1

There you have it: root -1 = 1

#19

Root -1 = -1^1/2 = ((-1)^2)^1/4 = 1^1/4 = 1

There you have it: root -1 = 1

Cant see a direct flaw in the method...

BUT

Assume root(-1)=1

Then this implies (-1)=1^2=1

But this is a contradction as we assumed root(-1)=1.

Therefore root(-1)=/=1

*Last edited by Mask_of_Terror at Aug 22, 2008,*

#20

EDIT: Miss read.

Hmm...emma think about this one...

There is a flaw in the last line: the other fourth roots of one weren't considered (-1, i, -i), and in this case, it's i and -i that are the correct roots, not -1 or 1.

#21

There is a flaw in the last line: the other fourth roots of one weren't considered (-1, i, -i), and in this case, it's i and -i that are the correct roots, not -1 or 1.

I feel like such a n00b...totally shouldve seen that one

#22

I feel like such a n00b...totally shouldve seen that one

Meh, my maths teacher showed me that one, I didn't see it either.

It's similar to this:

x=-2

x^2=4

x=2

-2=2

#23

I have a question concerning Series and Sequences.

The first term, U1, is 2.

The common difference, d, is 5.

And the series, Sn, is 119.

How would you find n using (n/2)(2U1+(n-1)d)?

The first term, U1, is 2.

The common difference, d, is 5.

And the series, Sn, is 119.

How would you find n using (n/2)(2U1+(n-1)d)?

#24

Meh, my maths teacher showed me that one, I didn't see it either.

It's similar to this:

x=-2

x^2=4

x=2

-2=2

No, if it's stuff like X^2 = 16 it would be like.. x=4 , x = -4.

#25

One is the loneliest number

#26

bump

serious help plz

differentiate the scalar function

f(x)= (cos(X),X,-X) x (sec(X),-X^2,2X)

f'(x)=________________

(the small "x" in the middle is actually a dot in the problem)

serious help plz

differentiate the scalar function

f(x)= (cos(X),X,-X) x (sec(X),-X^2,2X)

f'(x)=________________

(the small "x" in the middle is actually a dot in the problem)

#27

That's a weird problem - never seen anything of that sort.

Taking the gradient of each would give you (-sin(x), 1, -1) and (sec(x)tan(x), -2x, 2) respectively. If you apply the product rule and do the dot product and get some definitive answer. I doubt that's the way to go though.

It's a weird problem. I've only seen it in 3-d, never in 1-d.

Taking the gradient of each would give you (-sin(x), 1, -1) and (sec(x)tan(x), -2x, 2) respectively. If you apply the product rule and do the dot product and get some definitive answer. I doubt that's the way to go though.

It's a weird problem. I've only seen it in 3-d, never in 1-d.

#28

thats a trip, but 9x if x=.999, should be approx. .8991, thats cool though

Meh, my maths teacher showed me that one, I didn't see it either.

It's similar to this:

x=-2

x^2=4

x=2

-2=2

anytime you use squares you have two solutions, the square root of 4 is not 2, its plus or minus 2

*Last edited by Shredzorz at Sep 2, 2008,*

#29

One is the loneliest number

although two can be as bad as one

#30

Cant see a direct flaw in the method...

BUT

Assume root(-1)=1

Then this implies (-1)=1^2=1

But this is a contradction as we assumed root(-1)=1.

Therefore root(-1)=/=1

isnt root (x) = ±x?

#31

Meh, my maths teacher showed me that one, I didn't see it either.

It's similar to this:

x=-2

x^2=4

x=2

-2=2

x=-2

x^2=4

x^2 - 4 =0

(x+2)*(x-2) = 0

x1 = -2

x2 = 2

two solutions

I think my math prof was once going on about when you use the square root operator you have to write that the

*absolute*value of the sqrt() = whatever

I'm not sure anymore since that was like 3 math classes back

#32

Americans say maths without the 's'

#33

Americans say maths without the 's'

funny really isnt it

#34

Does anyone here take Math HL (IB).

I do, and it's rape.

I do, and it's rape.

#35

anytime you use squares you have two solutions, the square root of 4 is not 2, its plus or minus 2

I'm aware of that. I was demonstrating how to arrive at an invalid proof.

#36

Does anyone here take Math HL (IB).

I do, and it's rape.

I've never seen the word 'rape' used in that context before.

#37

^Old. Try this

7+7=-2

10+4=2

Yes there's already a thread on this, search math/science help thread.

Meh, my maths teacher showed me that one, I didn't see it either.

It's similar to this:

x=-2

x^2=4

x=2 OR -2

Fixed

#38

Oright guys, got a couple questions, admittedly easy, but i'm trying to work out what im doing wrong. So could you give me the answers in steps thanks

Expand the brackets and write each results as simply as possible:

(root3 + 7)^2

I know that the answer is 52+14 root3 but i dont see why...

(5+2 root3) (root5 - root2)

The answer to this one is 13, but again, im not sure why thats the answer :O

Expand the brackets and write each results as simply as possible:

(root3 + 7)^2

I know that the answer is 52+14 root3 but i dont see why...

(5+2 root3) (root5 - root2)

The answer to this one is 13, but again, im not sure why thats the answer :O

#39

I'm stuck on this question in my math homework, so can anyone work this out or at least tell me how to work it out? I just can't get my head round it:

For a light metal beam of length L m, carrying a load at it's midpoint, the sag S cm varies as the cube of the length.

Given that S = 1.8 when L = 5, calculate the sag when the length L is 8.4 metres.

Cheers. I don't think it's worded badly, but I don't understand what it's asking.

For a light metal beam of length L m, carrying a load at it's midpoint, the sag S cm varies as the cube of the length.

Given that S = 1.8 when L = 5, calculate the sag when the length L is 8.4 metres.

Cheers. I don't think it's worded badly, but I don't understand what it's asking.

#40

Sooo....

2+2=4?

2+2=4?