For the math elitists.

There is a 5'x5'x5' cube box sitting on the floor, against a wall. There is a 25' ladder leaning against the wall in such a way that the ladder touches the wall, the floor, and the top edge of the box that is furthest from the wall. (so that the ladder forms a triangle with the wall and floor.)

How far from the wall is the bottom of the ladder? There are two answers.

A guy at work asked this one and I couldn't figure it out. I did make some pretty looking math though.

Originally Posted by Mealworm

There is a 5'x5'x5' cube box sitting on the floor, against a wall. There is a 25' ladder leaning against the wall in such a way that the ladder touches the wall, the floor, and the top edge of the box that is furthest from the wall. (so that the ladder forms a triangle with the wall and floor.)

How far from the wall is the bottom of the ladder? There are two answers.

A guy at work asked this one and I couldn't figure it out. I did make some pretty looking math though.

I worked it out using quadratic equations.
I worked this in my head so I maybe wrong XD
20' is what I got.
Given that we can't have a negative distance from the wall, this is the only result that is possible.

I've got one.
An entire 2nd year University Computer Programming class could not answer this question (except for me):
Two men paint tiles.
It takes one of the men a minute more than the other man to paint a tile.
They paint 27 tiles in an hour.
How long does it take each man to paint 1 tile?

Originally Posted by oni_lunk

I worked it out using quadratic equations.
I worked this in my head so I maybe wrong XD
20' is what I got.
Given that we can't have a negative distance from the wall, this is the only result that is possible.

That answer is not correct because the ladder would not touch the box. I've used a graph to get an approximate answer and I've found that it is close to either 24 or 6.5.

Originally Posted by Mafoofoo

A maths problem?

Here is an elementary one. Like the most basic, simplest one I could come up with.


I drew it on paint since I don't know how to type the intergral symbol without going "int".

x^2 + c

Originally Posted by CPU0

Sorry to double-post, but this warrants its own.

I tried to solve it, but I had recorded it incorrectly, so I screwed up. I was thinking of what the solution was correctly, which I eventually found online...

The rectangular part formed by 2 pieces is 3x5 in the first, and 2x8 in the second. That makes for a 1 square difference. Also worthy of note is that the two triangles are not similar. Their angles are different. I don't really feel like doing the trig to show their actual angles, but I will say:

2/5 != 3/8
(the tangents of the smallest angle on both.)

Originally Posted by Soren707

Alright, this is for over-the-summer Calc. homework. Not sure about these questions though.

Confirm the limits algebraically:

** ^ denotes: to the power of** (for ex. 3x^2 means 3x squared)

1.) The limit as x approaches 0 of (5x^3 + 8x^2) / (3x^4 - 16x^2).
*I know the answer, I just don't know how to do it.*

2.) The limit as x approaches 0 of ((sin 2x) / x).

3.) The limit as x approaches 0 of ((sin^2 of x) / x).

A rock released from rest to fall on a small airless planet falls y= gt^2 times m in t sec, g a constant. Suppose that the rock falls to the bottom of a crevasse 20 m below and reaches the bottom in 4 sec.

a) Find the value of g.

b) Find the average speed for the fall.

c) With what speed did the rock hit the bottom?

Thanks for ANY help I can get!!!!!

I'm not going to answer all that... what don't you understand?

For those of you struggling with math, I highly suggest this video. It's helped me a lot.

I envy you all.

Here's one for you all, it's from the math I'm learning now:

Decide the Hesse-Matrix of

Originally Posted by Mealworm

There is a 5'x5'x5' cube box sitting on the floor, against a wall. There is a 25' ladder leaning against the wall in such a way that the ladder touches the wall, the floor, and the top edge of the box that is furthest from the wall. (so that the ladder forms a triangle with the wall and floor.)

How far from the wall is the bottom of the ladder? There are two answers.

A guy at work asked this one and I couldn't figure it out. I did make some pretty looking math though.

Using basic Euclidean geometry I got as far as

(h-5) * (d-5) = 25
h^2 + d^2 = 625

Where h is the height of the ladder where it touches the wall and d is the distance from the wall where it touches the ground.

Then I got stuck, gave up, and used a CAS to solve the two equations. The two solutions it gave me were 6.3 and 24.2--pretty much what Mealworm came up with.

I'm working on that.

Also, one that I solved was this:

There are three numbers below. A letter stands for a digit and there are no repeats of digits.
Find the equation's solution.

USA
+ USSR
---------
PEACE

Originally Posted by Mafoofoo

A maths problem?

Here is an elementary one. Like the most basic, simplest one I could come up with.


I drew it on paint since I don't know how to type the intergral symbol without going "int".

Calculus iz elementary maths lololol

by the way, x^2 + c, assuming the squigely next to the integral is 2. Of course, I did it the short way.

The three solution pairs are (x,y):

0,1
1,2
2,3

Originally Posted by oni_lunk

I've got one.
An entire 2nd year University Computer Programming class could not answer this question (except for me):
Two men paint tiles.
It takes one of the men a minute more than the other man to paint a tile.
They paint 27 tiles in an hour.
How long does it take each man to paint 1 tile?

Let's say,
1 minute to paint tile for the fast guy. So, they do even amounts, 14 for the fast and 13 for the slow.

Let's see if it adds up:

14 minutes for the fast one, 26 for the slow...that's too quick, so lets try 2 minutes.




1:30 for the quick one
2:30 for the second..

Not sure if that's right but, I tried.


EDIT: Or it could be:

60/4=15
60/5=12
12+15=27


One man takes 4 minutes to paint a tile, the other takes 5..


Excuse me, I have a headache now.

Eturnus_Frost... That is right. Four for the fast. And five for the slow. At those rates, the fast one can make 15 in an hour and the slow one can make 12. 15 and 12 is 27.

Originally Posted by Mjr162006

Eturnus_Frost... That is right. Four for the fast. And five for the slow. At those rates, the fast one can make 15 in an hour and the slow one can make 12. 15 and 12 is 27.

I'm surprised I got that to be frank.

I have a really tough one for you guys. Try to solve this one.




It has a closed form in terms of elementary functions.

NEVER BEEN GOOD AT THIS STUFF!
=(

sin(x/y)=y

using implicit differentiation, find the derivative to solve for slope to find the equation for the tangent line of the function passing through (2,3)

*hint y-y(sub 1)=m(x-x[sub 1])

Originally Posted by Matt

sin(x/y)=y

using implicit differentiation, find the derivative to solve for slope to find the equation for the tangent line of the function passing through (2,3)

*hint y-y(sub 1)=m(x-x[sub 1])

y'=(x cos(x/y)/y^2-1)-cos(x/y)/y

The equation of the tangent line is a messy decimal number. But it is close to

y=-1.087x+5.175