Math / Science

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I had this question after viewing Google earth optimal conditions..

Okay google earth is primary video card related.

I have a follow up question.
If most expensive video card is purchased will it be better than second most expensive video card?

Is this called
big o
where I need to figure out what video card will result in performance increase and how much increase that will be?
I am working on a college science presentation, with historical contexts, and I absolutely must have YBCO wire, I know there are other HTS wire out there, but due to the context, historical significance of YBCO, and research involved, I must have YBCO wire
Hi to all,

I would like to be able to write equations to model my tracked vehicle which has a mass m=200Kg.
My skid-steering vehicle uses one track per side with a rubber belt made in 100% natural rubber, please refer to the next photo to get a more detailed idea.
Since I mounted an IMU in its geometric center, I can read  both the angular velocites and the accelerations along the three axis plus the heading, the pitch and yaw angles in degrees.

I would like to be able to write a model for the vehicle in order to simulate and study its outputs depending on specific inputs.

Each track has a length L=1000 mm, a width W=330 mm and a lug height, H = 32 mm.
The vehicle is Lv= 1000 mm long and Wv=900 mm width.
There are no suspensions, but I consider the rubber track as the combination of a spring, coefficient K, and a damper, coefficient b. The rubber compression is about Dx =1,5 mm

By supposing a sinusoidal input below the track generated by the terrain profile, u(t) = Asin(wt), I was able to write the equation for the Z axis:

X(s)/Y(S)=(bs+k)/((m/2)*s^2 + bs+k) for the right track
X(s)/Y(S)=(bs+k)/((m/2)*s^2 + bs+k) for the left track

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Now, I would like to consider the lateral force Ft which acts on the robot during a turning motion.

Let's consider the vehicle during a steering maneuver on the left: while the YAW angle …
Hello and Good Morning Everyone,

              I am wondering how an Annual Percentage Rate (APR) of 26.70% be converted to a monthly rate.  Speaking hypothetically, I will put these numbers out here in order to capture or clarify my question.  An account has a balance of $500 with an APR of 26.70%. Given this information, how much interest would be added to this balance within one month?

              Thank you

I am trying to calculate the percentage of two column totals in Crystal Reports.  The formula below is the formula I am trying to use:

If {Command.cost}= 0 then 0 else sum{Command.cost}/sum{@labor gross}*100

What am I doing wrong?

Thank for your help in advance.
Exactly that
Ok, so I am a beginner to trigonometry, and how do you convert a decimal to a degree? I dunno if i worded it dorrect, but a website said tan 0.5 is 26.6. I still duno if thsts correct, but if it is, someone explain in good detail on how they got 26.6 degrees? I know how to invert, tan,sin,and cos, coordinates,cortesian coordinates, perpendicular lines, right angles, reciprocals (correct me if im wrong, fraction interchanging?) So can someone simply explain how they got 26.6? Thanks.
hi to all,

I have a vector in Matlab which contains samples acquired at 10Hz from an accelerometer mounted on a frame's vehicle.
This vector contains the acceleration values along the Z-axis.
The acquisition time is 103 seconds.

I would like to plot the frequency values in Hz since I'm trying to study the terrain frequency response.

I tried to use the fft function available in Matlab, but I do not know how to proceed.
Can you help me, please?

These are the values contained in my vector:

ans =
        1024           1
vibration =

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Is it related to the fact that we do not know any rule regarding their distribution to date?

For example we have generated lists of several billion Consecutive Prime Numbers and it turns out that there does not seem to be a rule regarding the gaps between each number or at least not on an acceptable human scale .. ... .....

There does not seem to be a rule regarding the gaps between each number …

Here you can download 2 of our small generated lists, the first one containing the first 10'000'000 and the second one containing the first 100'000'000 consecutive Prime Numbers all listed in the correct order with their exact positions, as well as the gap between each number.

Are there any available very long and detailled lists of Large Prime Numbers that allow for larger-scale analysis of the gaps between numbers ?

Or is there a mathematical rule to quantify those number gap or to know their emerging sequence?

Thank you in advance for your answers .. ... .....

Hello everybody,

It seems generally admitted that there are no negative prime numbers.

What are the rules that can affirm this?

Thanks in advance and happy new year to all.

Best regards,
I am looking for a single mathematical formula that takes in elevation, temperature, humidity and barometric pressure, and gives the speed of sound as an answer. I have found many simplified formulae which use only one variable to give an approximate answer but can't find one that provides a more accurate answer. I realize this may be out of the scope of experts exchange, but thought it can't help to ask.
Hi to all,

I have a vector " imu" with a size of 11497 elements. These elements are samples captured at a very high rate (the total time is 71 seconds so I think the frequency is about 160 Hz). Since I acquired all the other values at 10Hz, the size of all my other vectors is 719.

I would like to remove the oversampled elements from the vector " imu" in order to have only 10 samples per second.

Is there any way to do this? Can you help me, please?
Hi to all,

i'm having a problem with one of my old matlab scripts.
This script worked very well on a previous version of Matlab, but now I'm running it on a different machine and on a different Matlab version (R2017b) and it gives me this error:

Index exceeds matrix dimensions.
Error in cusum (line 36)
y   = x1(:,c_y) - mean(x1(:,c_y));
Error in original (line 269)
      [ckc,slc]=cusum(Ic(:,2)); %% PROBLEMA 

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Please, can you try to help me?
I attached to this post all the matlab files (i renamed them with *.txt extension) and also the txt file to use to populate the vectors.

The main matlab file is 'original.m':

clear all, close all
addpath '/home/rocco/Documents/MATLAB/code/function'
% figure(1)
% set(1,'units','normalized','position',[0.142187 0.484722 0.307813 0.447222],....
%         'name','Path','numbertitle','off');
%     set(gca,'FontSize',11);
% figure(2)
% set(2,'units','normalized','position',[0.457031 0.484722 0.264063 0.447917],....
%         'name','Equivalent track','numbertitle','off');
%     set(gca,'FontSize',11);
% figure(3)
% set(3,'units','normalized','position',[0.009 0.13 0.482031 0.806944],....
%         'name','Terrain estimation','numbertitle','off');
%     set(gca,'FontSize',11);
% figure(4)
% set(4,'units','normalized','position',[0.00351563 0.0465278 0.214453 0.893056],....
%         'name','Path','numbertitle','off');

%% Load data

% First campaign january 2015

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Suppose I need quantity Q grams of honey, and I can buy packs of honey in either 340g or 454g pack sizes. These packs cost 1.79 and 2.19 respectively (cost per kilo is therefore 5.26 and 4.82 respectively)

I buy m packs of 340g and n packs of 454g

Question: express m & n in terms of Q in order to minimise cost for any given Q.

I believe this is a solution:

But this maybe overbaking it (the least common multiple of 340 and 454 is 77180)

Wandering if I'm missing a shortcut somewhere.

Dear experts,

In the attached image I have the Principal solution for positive and negative sin theta. The image shows how the negative theta values are reflected as positive alpha values.

Can someone please guide me to an article in public domain for equivalent workings of Cot, cosecant and secant theta.

Thank you
I'm running SQL Server 2012.. .wondering if anyone has seen any procedures of functions for doing Monte Carlo simulations on financial data such as the stock markets.

Seems there may be a function in 2016, but we're not there yet.

Anyone have experience in this area?
Thank you!

(I'm also using Coldfusion if there is something there too)

During the past 10 years, the level of demand for a company's product has increased from 1,150 units per day to 2,150 units per day. What was the average annual compound growth rate over this period? Show the solution.

1.8695 = (1+g)^10
Growth Rate=10%
What are typical application in the life science industry ?

Bio reactor? how does a bio reactor work?
Car dealer told me 15" saves more fuel & is more suited for Sienta hybrid  (& Airwave)
while 16" is more suited for Toyota C-HR.

I like 16" so that my bumper is not too low & often get scratched when reverse-parking
or head-in near high pavements (have seen pavements of 9-10" higher than parking

Is this true that 15" saves more fuel?

which one can accelerate faster or no diff?

which one is more stable ?  I tend to think lower centre of gravity makes
an object less likely to overturn
How to calculate ''32% Undergraduate Grade Point Average?
Hello again,

We forgot to ask you a question about prime numbers.

We are indeed releasing a number primality check tool for which there is no actual size limit beyond the one we have imposed for material resource issues.

However, it is often mentioned the existence of ILLEGAL prime numbers and we do not quite understand the meaning of being able to define a number, which ever it may be, illegal.

However, given the nature of our tool which has no processing limit, we do not wish to have any problem with the authorities.

What is your opinion on the issue, do you think we expose ourselves to any risk by releasing such a tool?

Looking forward to hearing from you.

Best regards,


P.S. In attachment you will find a text file contains the 3 previous and the 3 next numbers following the first illegal known one that contains 1401 digits.
I am trying to find the term used in chemistry to describe the tendency of a 2-way chemical reaction to prefer one chemical combination over the other, such as in Keto-Enol in organic chemistry. I can only recall using the term affinity, but that is not precisely what I am looking for.

This is a follow-up question to a previous thread located here:

Auto-fill a cell's color based on numeric RGB values and vice versa in Excel

In that thread, the solution (by Ejgil Hedegaard) includes an attached Excel file in which the fill color of a particular cell, automatically changes in response to entering various values in three other cells labeled R (red), G (green), & B (blue).

This functionality is tremendously useful for me (and I suspect will be for others) because it enables you to instantly view the new color resulting from changes in any of the RGB parameters (ie without the necessity of the four clicks typically required to obtain that information):

        Home > Fill Color > More Colors > Custom

(The file also includes a chart for quickly converting from RGB decimal to RGB hex and vice versa.)

Additionally, the solution to the thread contains the formula for calculating Excel's color code:

        ExcelColor = R + G *256 + B *256^2

For example:

        Red = 204
        Green = 102
        Blue = 255

is calculated as follows:

        ExcelColor = 204 + (102*256) + (255*256^2)
        ExcelColor = 16737996

It also displays the following for reversing the process (ie :

        R = C Mod 256
        G = C \ 256 Mod 256
        B = C \ 256^2 Mod 256

Are these three formulas math or code and what is the purpose of the backslash?

I'd like to take a list of intervals defined by pairs of numbers, eg

and convert this into a consolidated list counting any overlapping intervals as one, so the above example would give:

See attached drawing that illustrates this.

I want to do this with array/matrix operations, if possible, so I can implement in google sheets without coding.

Can you guys please suggest me some good free web sites for the preparation of mcat exam?