The Post Your Thoughts of the Moment Thread 2

[KefkaticFanatic]

SCIENCE small talk is best small talk though

[dahans]

Oh my... it feels like ages ago since I have last posted here.... I AM SORRY :S

[Toby]

I can't study, how to study?

Someone help me with gradients and straight lines and stuff

[MaestroUGC]

Oh, hey dahans.

[Sir Dino]

gradients and straight lines and stuff

algebra?

[Toby]

Sorta, like Gradient m = y= mx+c

and y intercept stuff

[Sir Dino]

pm me, I love a good slope puzzle

[blueflower999]

It was always Y=MX+B for me. 

BTW, does anyone know what M and B stand for? Like I know that M is the slope and B is the Y intercept, but why M and B? Why not S for slope and I for intercept? Why such random letters?

[Sir Dino]

It was always Y=MX+B for me. 

BTW, does anyone know what M and B stand for? Like I know that M is the slope and B is the Y intercept, but why M and B? Why not S for slope and I for intercept? Why such random letters?

same.

m is the slope, b is the y-intercept?

[Toby]

My math teachers a weirdo though so yeh, also anyone know formulaes for 3D shapes? Got a test tomorro, aiming for 60%

[Sir Dino]

My math teachers a weirdo though so yeh, also anyone know formulaes for 3D shapes? Got a test tomorrow, aiming for 110%

ftfy

It depends what you want, surface area, volume?

[Toby]

Both actually!

[Mashi]

The variables' letter names have been being used for centuries and haven't necessarily changed form.  The "m" and "b" for slope and y-intercept respectively may have originally been abbreviations for words.  After a bit of research, "m" may have once originally been an abbreviation for the French word "monter," which means to climb (just as slope is a point climbing through the graph) and "b" may have been derived from the Latin word "batenhi," which means intersection.

In reality though, the variable used really doesn't matter.  If one wanted to say that b=qw+f for y=mx+b, he/she would certainly be permitted to do so, as long as the proper numbers were substituted in (though, I don't think any teachers would enjoy that, so don't do that!).

And yes, which formulas for which shapes in particular, TheBoyWhoCriedWolf?  I could help you out with a few derivations too, so that you don't need to memorise them, if you would like.

[Sir Dino]

Not that you could google it, but:

Rectangular Prism: (L= length, W=width, H=height)
SA= 2LW + 2(L+W)H
V= LWH

Circular Prism: (π= pi. r=radius)
SA= 2πR² + 2πRH
V= πr²H

Triangular Prism: (b= base, l=length, S_1, S_2, S_3= sides that make up perimeter of base)
SA= bh + (S_1+ S_2 + S_3)H
V= 1/2bhl


volia~ hope that helped, Mashi pretty much covered the slope c:

[Cobraroll]

Volume of any regular shape: V = Int(Int(Int dx)dy)dz). With the appropriate limits, of course. Does only apply for Cartesian coordinates.

Of course, in most practical cases, you'll have a much easier body to find the volume of. Aamir covered most of it, but he forgot the common sphere: V = 4/3 * pi * R³. Surface area would be 4 * pi * R² (yes, four times the area of a circle). Divide into halves as it suits you, just remember to add all the partial circles you get to the total surface area.