||| - Official Maths / Science Thread - |||

[nervewrecker]

yuh gone again using pi? 0.785 * (raduis *2) so hard to use? smh

HINT: to solve the problem real easy work with liters & remember 1000 liters = 1m^3 too.

[toyota2nr]

The answer is PENIS, big hard throbbing, veiny, hot, blood engorged manmeat!

WTF!!!

Sicko.

I call for a no confidence motion in rs.

[black start]

^rs is police not politician.....so is better to go police complaints commission

[Corn Bird]

:lol:

those rounded off numbers does make a big difference eh. ah just saying.

gracen -- nervewrecker is correct. Pi/4 is .7854..

your mistake seems to be that you're using Pi=22/7

this is just a crude approximation (but for some reason is taught as fact by some teachers)

Pi cannot be expressed as a fraction (it is irrational see http://en.wikipedia.org/wiki/Irrational_number)

notice that

22/7 = 3.142857142857142857 (the string '142857' repeats)

while

Pi=3.14159265358979323846264338327950288419716939937510

to 50 decimal places. notice there is no repetition in the decimal expansion of Pi

for calculations, people truncate the decimal expansion of Pi to the accuracy that they want.

[Ronaldo95163]

true^ but in most cases a decimal off doesn't make a difference in a test. I understand that it could be crucial for Real World Applications though.....

[black start]

true^ but in most cases a decimal off doesn't make a difference in a test. I understand that it could be crucial for Real World Applications though.....

exactly, and that's why there is a pi function built into most scientific calculators

[nervewrecker]

^^^

very true, I woulda take 0.78 or 0.79 as the answer btw, 0.8 is too far off.

In real world applications there is a lot more to that question I gave though. The tank base supposed to be 100m^2 buts that's as close of a radius I could give to get as close to 100m^2 (1000m^3).
0.264 US gallon is 1 liter btw see why I say work with liters? suck eye bizness. (then man does screw up they pan when I finish the exam in 15 minutes & is 3 hours long, is facking giveaway answers).

I shoulda give allyuh some with pump efficiency, watts & brake horsepower though, then allyuh woulda be skipping.

nobody tackle the one with the 2 circles & relation in area though. that question is not open to tr1ad btw.

[Ronaldo95163]

true^ but in most cases a decimal off doesn't make a difference in a test. I understand that it could be crucial for Real World Applications though.....

exactly, and that's why there is a pi function built into most scientific calculators

It's an approximated value though..

[nervewrecker]

nah, I think the pi function on the calculators are the full works.

press pi & =. see what you get?

[black start]

I have one

[nervewrecker]

I have one

throw yuh frame eh.

[Ronaldo95163]

^^^

very true, I woulda take 0.78 or 0.79 as the answer btw, 0.8 is too far off.

In real world applications there is a lot more to that question I gave though. The tank base supposed to be 100m^2 buts that's as close of a radius I could give to get as close to 100m^2 (1000m^3).
0.264 US gallon is 1 liter btw see why I say work with liters? suck eye bizness. (then man does screw up they pan when I finish the exam in 15 minutes & is 3 hours long, is facking giveaway answers).

I shoulda give allyuh some with pump efficiency, watts & brake horsepower though, then allyuh woulda be skipping.

nobody tackle the one with the 2 circles & relation in area though. that question is not open to tr1ad btw.

the answer was 78.5%.....i didn't multiply by 100 hence the reason for the incorrect placement of the decimals.


But for CXC i think the limit is 0.2...i think anything else outside of that range would be wrong so 0.8 correk according to CXC

i'll try the question the other circle

[nervewrecker]

http://www.engineeringtoolbox.com/

here is a nice place to do some reading btw guys.

I think I got some of my spreadsheets & calculators there (all them things on my old hard drive locked).

[black start]

I have one

throw yuh frame eh.

i does always cho meh frame......but on big oman eh.....

come and watch me in action, you may learn a thing or two....

[Corn Bird]

nah, I think the pi function on the calculators are the full works.

press pi & =. see what you get?

my guess is that some calculators can symbolically manipulate Pi (similar to how they can multiply complex numbers). but they cannot hold the full decimal expansion of Pi. this would be impossible. it is some sort of competition to calculate Pi up to some large number of decimal places

In August 2010, Shigeru Kondo used Alexander Yee's y-cruncher to calculate 5 trillion digits of pi. This was the world record for any type of calculation, but significantly it was performed on a home computer built by Kondo.[16] The calculation was done between May 4 and August 3, with the primary and secondary verifications taking 64 and 66 hours respectively.[17] In October 2011, they then broke their own record by correctly computing ten trillion (1013) digits using the same method but with better hardware.[18][19]


see http://en.wikipedia.org/wiki/Approximations_of_%CF%80#20th_century

[nervewrecker]

you know what, just for the hell of it, take one for the night black start (I slepy):

a 1000 horse power motor on a pump with 12" impellers (centrifugal pump) & the center of the shaft 40 feet above sea level. 4" intake pipe primed & inserted into a reservoir with the waters surface at sea level.
tell me how much water it does pump out per second.

edit:

to make things easy, tell me how good that pump will "suck" up de watah!

If you get the answer wrong that mean you does bul mampie & say big oman.

[Ronaldo95163]

http://www.engineeringtoolbox.com/

here is a nice place to do some reading btw guys.

I think I got some of my spreadsheets & calculators there (all them things on my old hard drive locked).

Nice share...won't be able to read all of it tho.....getting a headache. Mechanical Engineering looks like a nice field....lots of hard work needs to be put into it though.

In the meanwhile solve for x guys:



Logs was always my fav topic btw

[nervewrecker]

nah, I think the pi function on the calculators are the full works.

press pi & =. see what you get?

my guess is that some calculators can symbolically manipulate Pi (similar to how they can multiply complex numbers). but they cannot hold the full decimal expansion of Pi. this would be impossible. it is some sort of competition to calculate Pi up to some large number of decimal places

In August 2010, Shigeru Kondo used Alexander Yee's y-cruncher to calculate 5 trillion digits of pi. This was the world record for any type of calculation, but significantly it was performed on a home computer built by Kondo.[16] The calculation was done between May 4 and August 3, with the primary and secondary verifications taking 64 and 66 hours respectively.[17] In October 2011, they then broke their own record by correctly computing ten trillion (1013) digits using the same method but with better hardware.[18][19]


see http://en.wikipedia.org/wiki/Approximations_of_%CF%80#20th_century

oh goar, I meant its not 3.14 the scientific calculators use

I could lime with allyuh yes.

[nervewrecker]

I hate logs gracen, not me & that

[Ronaldo95163]

ln(2x-3)+ln(x+4)=ln(2x^2+11)
ln(2x-3)(x+4)=ln(2x^2+11)
ln 2x^2+8x-3x-12= ln 2x^2+11
ln 2x^2+5x-12=ln 2x^2+11
***Dropping Lns on both sides***
2x^2+5x-12=2x^2+11
5x=11+12
5x=23
x=23/5
x=4.6

Best topic in Add math imo

Anybody like Remainder and Factor theorem? That topic very fresh as well

[Corn Bird]

consider the set of natural numbers {0,1,2,3,....}

this set is infinite

now consider the interval 0 to 1 on the *real* number line. so this interval contains numbers like 1/4, 1/2, Pi/4 etc. there are an infinite set of real numbers within this interval.

so the set of natural numbers is infinite. also the set of real numbers from 0 to 1 is infinite.

question: which of these two sets is larger, that is, is it possible for one infinity to be larger than the other?

[cinco]

buncha forkin nerds

[Ronaldo95163]

I don't think any of them would be larger. Wouldn't the interval between the numbers be the same

e.g
0-1
1-2
2-3
....

Kinda like in GP's when you find the Sum to infinity...in other words the limiting factor.....it's gonna seem as if you're getting closer but you never reach where you want to get...so i'm not sure as to what the answer to that question is

[Corn Bird]

^

the set of natural numbers {0,1,2,3,....} has size/cardinality that is countably infinite

the set of real numbers from 0 to 1 has size/cardinality that is uncountably infinite

these are two different types of infinities, with an uncountable infinity being larger than a countable infinity

see http://www.econ.umn.edu/~msolis/Part5-3.pdf

this video lecture explains some of this (i didn't look at the entire thing)

[rollingstock]

Google why you no translate this page

[Ronaldo95163]

Question.
Exactly what happens when i type the sine (or cos or tan etc for that matter) of an angle into my calculator? I type it in and it magically gives me an answer, a number that is essentially unrelated to the angle I inputed. Is the calculator just reading off of a list created from people who used rulers to physically measure the distance on a graph or is there a mathematical function that defines it?

A calculator or computer program is not reading off of a list, but is using an algorithm that gives an approximate value of sine of a given angle. There are several such algorithms. Many times they only use the four basic operations (+, -, x, /) to find the sine or cosine or tangent of a given angle.

One way is to take a certain amount of terms (the more terms, the more accurate the approximation) from the Taylor series for sine:
sin x = x - x3/3! + x5/5! - x7/7! + ...,

where x is in radians. For example, to find out sine 23, first convert 23 to radians by dividing it by 180 and then multiplying by p. We get 23/180 p = 0.401425727958696 0.4014257. Then use the above formula to get the value of sin 0.4014257:

sin 0.4014257 = 0.4014257 - 0.40142573/3! + 0.40142575/5! - 0.40142577/7!
= 0.4014257 - 0.0107811296737492 + 0.000086864959350 - 0.000000333277256
= 0.390731102008345
Calculator would give directly Sin 23 = 0.390731128489274 so the formula hit it right for the first seven decimals (and there even exists and error estimate that tells you how big an error maximum you make when you use a certain number of terms from the Taylor series).
See how closely the polynomial formed from the first four terms of the Taylor series approximates the sine curve near origin.

In the picture they look identical but we know they are not exactly the same, just very very close - even the above calculation shows that.
Calculators often use the CORDIC algorithm to find values of trigonometric functions, which is based on thinking of the angle as the phase of a complex number in the complex plane, and then rotating the complex number by multiplying it by a succession of constant values.

In fact, the calculator or computer program uses some kind of algorithm based on the basic operations to calculate not only trigonometric values, but also square roots, values of hyperbolic functions and others. The branch of mathematics called numerical methods studies and develops these algorithms. It is an interesting field of mathematics, and one that surely has lots of applications. Of course if you study computer science you will encounter many of them.

[ruffneck_12]

haul allyuh ass

[Ted_v2]

haul allyuh ass

first thing i understand in this ched

[Corn Bird]

haul allyuh ass

buncha forkin nerds

you all can use computers or are even I.T. specialists

a lot of computer science/electrical engineering is mathematical. for example, Reed-Solomon error correcting codes used in CD's and DVD's are based on pure maths (linear algebra, finite fields etc) http://en.wikipedia.org/wiki/Reed-Solomon_error_correction

another example is modern cryptography which uses elliptic curves from algebraic geometry http://en.wikipedia.org/wiki/Elliptic_curve_cryptography




the basic attitude of I.T. and local engineers is to scorn maths. which is perhaps why local engineers are stuck maintaining imported technology rather than designing anything new



when next you complain about the stupidity of high school children, remember that these young children pick up their values from you



but you're right, trinituner is not the place to talk maths

no sense in feeding spongecake to corbeaux

[Bizzare]

gracen is definitely a virgin