222 replies to this topic

[Secret Igshar]

Math! Let's talk about it, solve fun problems, and all sorts of other awesome stuff.

So, on Monday in Calc 3, we did this really fun integral.

1 x
/ /
| | dy dx
/ /
0 x^2

That's the best I can do at rendering it into this. >_>; Anybody wanna take a crack at it? :>

[Deadly-Dreamer-X]

I just finished my maths exam this past Sunday.

But I did bad, I wasn't prepared and I was sick too. I think I failed.....

But not with the total average I got, I think I will pass but there is the chance I fail.

So, I am in the finals. I finished physics, was easy but hell lot of questions. u2sinO/2g baby!(O is theta).

I am still in 3rd LV (that's 11th std)

Calculus? Still haven't met it.

[Secret Igshar]

Calculus? Still haven't met it.

Fail. Calculus is quite possibly the most enjoyable class you can possibly take in any school ever. It's mostly fun because it's so easy.

YES, I SAID IT. Calculus is easy. It's the Algebra and Trigonometry that gets all muddled up in the Calculus that makes it "hard" for some people. Integrals and Derivatives are eeeeeasy shiz. <3


Also~ Coolest Math fact OF ALL TIME.

iπ
e + 1 = 0

Why is it so pretty? It uses addition, multiplication, and exponentiation exactly once each along with incorporating the important constants 1, 0, e, i, and π all into one, tiny little equation. <3

[Deadly-Dreamer-X]

Will, just let me get to 12th std peacefully and let me see it for my self.

[Lycanthrope]

Oh man, you saying Calculus is easy makes me feel like a failure for working my butt off in Pre-Calc just to have a low B. It's easily my worst subject.

[Secret Felix]

*tries to remember* I think this was the question, but I'll have to dig up my old math tourney paper to check. :<

A bag is know to contain a marble that is either red or green.

A green marble is added to the bag.

The bag is shaken, and a marble is removed. It is green.

The marble is replaced, the bag is shaken, and another marble is removed. It is green.

What is the probability that the remaining marble is red?

[Secret Igshar]

Oh man, you saying Calculus is easy makes me feel like a failure for working my butt off in Pre-Calc just to have a low B. It's easily my worst subject.

Calc is easy. Pre-Calc is a bitch. In Pre-Calc you need to know a shit-ton of obscure Trig formulas and identities along with lots of algebra tricks on top of learning the basics of WHY Derivatives and Integrals do what they do.

It's a pain until you get past the initial Limits. Once you start doing Derivatives and Integrals with shortcuts, the Trig and Algebra is the only difficult part. I still suck at Trig, so don't worry. >__>;

Who ever remembers that cos2x = cos²x - sin²x ? I didn't until my Professor brought it up lol.


Also~ Probability problems... D:

I think 25%. Since there are 2 Marbles. The first one is Red or Green. The second is definitely Green. (50% + 0%)/2 = 25% :>

[Deadly-Dreamer-X]

A bag is know to contain a marble that is either red or green.

A green marble is added to the bag.

The bag is shaken, and a marble is removed. It is green.

The marble is replaced, the bag is shaken, and another marble is removed. It is green.

What is the probability that the remaining marble is red?

Wow! And I thought Probability is the easiest thing around.

EDIT:

Percentage?

I never got there.

Except where they ask me about 52 cards and 4 removed what is the probabilty a card a daimond and other stuff.

Also mixed with Permutation and Comabination.

48C4 something like that.

Also Die and Coin and those thing.

Edited by Deadly-Dreamer-X, 11 February 2010 - 02:08 PM.

[Lycanthrope]

Yeah, those trig formulas were just so pointless that I just couldn't remember it at all.

Probability and statistics are easily my strong suit with math. I'm opting out of AP Calc next year for the AP Stat solely because I doubt I will go into a profession that will require calculus. And I'll do much better in Stat

[Deadly-Dreamer-X]

Yeah, those trig formulas were just so pointless that I just couldn't remember it at all.

Probability and statistics are easily my strong suit with math. I'm opting out of AP Calc next year for the AP Stat solely because I doubt I will go into a profession that will require calculus. And I'll do much better in Stat

Economics? Cause they also need high amount of Statistics there.

Arithematic Progression? Did you guys ever seen Geometric progression?

I need calculus, I learned some derivation using Calculus.

Trig is my fav.

sinx-siny = - 2 cos x+y/2 sin x-y/2

[Waker]

Taking year-length Calculus next year~ Loved trigonometry and sequences in pre-cal.

[Secret Felix]

Since we're discussing this on aim, and I can't remember the answer..



Possible Combinations

G₁G₂
G₁G₁
G₁G₂
G₂G₁
G₂G₂

and

R₁G₁
R₁R₁
R₁G₁
G₁R₁
G₁G₁

Since you know you drew a green twice, you can eliminate any where greens are not drawn. This leaves us with:

Possible Combinations

G₁G₂
G₁G₁
G₁G₂
G₂G₁
G₂G₂

and

R₁G₁
R₁R₁
R₁G₁
G₁R₁
G₁G₁

Then it's just wanted/total, so 1/5, or 20%. I think. >___>:

[Secret Igshar]

Then it's just wanted/total, so 1/5, or 20%. I think. >___>:

That makes sense, I suppose. >.>

HMMMM. What about this probability problem?

Jeffrey the Squirrel throws five acorns from his tree, trying to hit Albert the Squirrel in the neighboring tree. He's a pretty good shot and judges his chances to hit from where he is, given wind speeds and other such things that Squirrels don't actually know about, are thirty-five percent. What are the odds that Jeffrey will hit Albert with at least three of the acorns, assuming Albert does not move when hit?

[Secret Felix]

That makes sense, I suppose. >.>

HMMMM. What about this probability problem?

Jeffrey the Squirrel throws five acorns from his tree, trying to hit Albert the Squirrel in the neighboring tree. He's a pretty good shot and judges his chances to hit from where he is, given wind speeds and other such things that Squirrels don't actually know about, are thirty-five percent. What are the odds that Jeffrey will hit Albert with at least three of the acorns, assuming Albert does not move when hit?

~18%

*crosses fingers*

Edited by Artemis, 17 February 2010 - 09:56 PM.

[Lexaeus]

That makes sense, I suppose. >.>

HMMMM. What about this probability problem?

Jeffrey the Squirrel throws five acorns from his tree, trying to hit Albert the Squirrel in the neighboring tree. He's a pretty good shot and judges his chances to hit from where he is, given wind speeds and other such things that Squirrels don't actually know about, are thirty-five percent. What are the odds that Jeffrey will hit Albert with at least three of the acorns, assuming Albert does not move when hit?

My guess is around 4 percent.

[Secret Igshar]

~18%

*crosses fingers*

My guess is around 4 percent.

~23.5%, actually.

You need to use the formula:

P = _nC_r x p^r x q^n-r

where n is the amount of shots and r is the amount you want him to make successfully. p is the probability of success while q is the probability of failure (1-p). You have to do this 3 times, for r=3, r=4, and r=5 and subsequently sum up the three probabilities to get the probability of him connecting with AT LEAST three acorns.

[Reasonable Doubt]

[Lexaeus]

~23.5%, actually.

You need to use the formula:

P = _nC_r x p^r x q^n-r

where n is the amount of shots and r is the amount you want him to make successfully. p is the probability of success while q is the probability of failure (1-p). You have to do this 3 times, for r=3, r=4, and r=5 and subsequently sum up the three probabilities to get the probability of him connecting with AT LEAST three acorns.

I knew my answer wasn't right because I wasn't expressing the other probabilities of the last two throws or if two of the first three throws missed.

lol wut i did (.35)^3=.04 (about)



1.) 37.32 m
2.) toward the weak one straight on
3.) away from the raptors?

Also. Iggy, is that original integral in post #1 equal to (1/6)?

Edited by Lexaeus, 18 February 2010 - 12:04 AM.

[Secret Igshar]

Also. Iggy, is that original integral in post #1 equal to (1/6)?

Yush.

NEW PROBLEM.


Find the volume contained beneath the graph of

z = 4 - x² - y²

in the first octant. (Problem in 3D)

Hint~ You're gonna use the formula:

/ /
| | f(x,y)dA
/ /
.R

[Lexaeus]

Yush.

NEW PROBLEM.


Find the volume contained beneath the graph of

z = 4 - x² - y²

in the first octant. (Problem in 3D)

Hint~ You're gonna use the formula:

/ /
| | f(x,y)dA
/ /
.R

So...this one look took forever x_X

Spoiler

2pi

ill scan my work to show these buggers how its done