Current status http://status.fireden.net/ Hidden site now up at http://ydt6jy2ng3s3xg2e.onion/

### Threads by latest replies - Page 3

(36 replies)
No.10987403
Hello /sci/ I am interning at a middle school as a sub teacher and I want to explain 7th graders how to derive the quadratic formula.
What do you think? Is this clear enough for them to get the main idea? (It is an AP algebra class). I made this derivation myself since a typical derivation you find on the web is too cryptic and doesn't explain the main idea well.

Problem: derive the solution of the quadratic equation $ax^2 + bx + c.$
Our derivation is based on the identity: $(a+b)^2 = a^2 + 2ab + b^2 \qquad (1)$
Any quadratic equation can be transformed to the following form:
$(x + m)^2 = d \qquad (2)$.
Why is it important? Because m and d are constants and we have to solve for just one uknown variable x by taking the square root on both sides:
$x + m = \pm \sqrt{d}$
$x = -m \pm \sqrt{d}$
Let's consider a simple example $x^2 + 6x + 5 = 0$
How dow we convert it to the identity (1)? Well we can first re-write it as
$x^2 + 2\cdot x\cdot 3 + 5= 0$
Notice the second term looks like the second term in (1) so b=3. But obviously $b^2$ then needs to be 9. So we can add 4 to both sides of the equation:
$x^2 + 2\cdot x\cdot 3 + 5 + 4 = 4$
$x^2 + 2\cdot x\cdot 3 + 3^2 = 4$
$(x + 3)^2 = 4$
This is the same as form (2). We can now solve it:
$x +3 = \pm \sqrt{4}$
$x = -3 \pm 2$
$x=-1, x=-5$
Now we can apply the same technique to solving the general equation $ax^2 + bx +c = 0$. We first divide by a:
$x^2 + \dfrac{bx}{a} + \dfrac{c}{a} = 0$
Now we take $\dot{b} = \dfrac{b}{a}, \dot{c} = \dfrac{c}{a}; \qquad$ And the equation becomes:
$x^2 + \dot{b}x + \dot{c} = 0$
Let's add a certain unknown number $d$ to both sides:
$x^2 + \dot{b}x + \dot{c} + d = d$
[cont'd]
31 posts and 3 images omitted
(68 replies)
219KiB, 1292x918, great filter.png

## The Great filter

No.10985145
I postulate that the great filter preventing civilizations from colonizing the universe is something which abuses the very qualities that allow civilization to develop in the first place. The creation of self replicating molecules has been reproduced in laboratory conditions, and doesn't seem all that difficult to achieve on any planet with hydrocarbons (basically all of them). Evolution of life from that point on would seem to naturally follow from that. Having determined that pretty much everything leading up to this point isn't so astonomically unlikely, we must conclude that the filter is either at a point slightly ahead of us, or we are currently moving through it.

So, what social qualities must a species possess to allow the development of civilization, and can you think of any particular entity or entities around us that take such profound advantage of those qualities as to reduce a civilization to eventual ruin?
63 posts and 3 images omitted
(319 replies)
183KiB, 582x465, 988569e478567.png
No.10983742
Why are UFOs considered to be in the realm of conspiracy theories / the paranormal? Isn't the existence of aliens probable?
314 posts and 18 images omitted
(8 replies)
509KiB, 835x305, transcend.png
No.10989690
>there's an afterlife that's essentially an empty void except a bunch of exceptionally difficult math problems
>Whenever a great mathematician dies he goes here
>Everyone else that dies goes to some other shithole or doesn't go anywhere idk
>If all problems are solved they are all taken out of the void into some paradise.
Who would be in this afterlife?
Other than me of course because of my work in /sci/ shitposts.
3 posts omitted
(6 replies)
536KiB, 987x717, image.png
No.10988198
Rejoice!
Based Wang is going to unbald you by electrocuting you with a cap.
1 post omitted
(6 replies)
208KiB, 1562x1038, order of operations.png
No.10990219
In order of operations multiplication and division are on the same level, and I was told to evaluate them left to right when an equation contains both. However, I have been evaluating equations and find it doesn't matter if you evaluate left to right or not.
For example:
(6 * 8) / 100 = 0.48
6 * (8 / 100) = 0.48
Can you give me an example of a simple equation using only multiplication and division that evaluates incorrectly when not read left to right?
1 post omitted
(33 replies)
29KiB, 534x574, images (25).jpg
No.10988723
I love math.....
but math exam is horrible
I have not confidence to solve this shit in limited time
28 posts and 4 images omitted
(184 replies)
16KiB, 233x225, 1565992586203.jpg
No.10970658
>NOOO generic engineering is bad!!! You can't just play god!!!
179 posts and 64 images omitted
(129 replies)
1MiB, 2856x1904, FlyingCar.jpg

## Will People Ever Admit That Flying Cars Have Already Been Invented?

No.10983911
I'm sick of comments about flying cars. We have them and barring antigravity they're never going to be what you want them to be.
124 posts and 24 images omitted
(5 replies)
298KiB, 1600x920, table.jpg

## A Table

No.10990243
wouldn't the table just fall over if someone on the north side of it relative to the viewer just pushed it? Or does the length of the table make this harder? To me it seems like a bad table design. wth da vinci.

What are your thoughts on this sci?