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The Math / Science topic primarily includes discussions of mathematics, physics, statistics and economic analysis, but also biology, chemistry and other sciences.

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Can you please tell me if the calculations are correct?
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I am trying to check integration using two different methods, first by using [function (int)] and second by using summation. I am integration from high to low values (0.1 to 0). I got same result. However, from function I got positive value (0.005) and from summation, negative value (-0.005).  I am not sure if that because I am integrating from high to low values so I need to use (dr) in negative value when finding the integration using summation.

I used below code

 clear all;
  syms x y 
  y = -x; 
  for i=1:20

Open in new window

I see this cool animated GIF that shows a prism refracting light. Can the light also go the other way, and make the light more focused?

Is it true that a prism that refracts light as well as focuses light?

I would like to implement a fast fixed point sine approximation for PIC24F microcontrollers on 16bit.
I started from here:
The approximation is done with polynomials: 3rd order up to 5th or even 6th order.
I am stuck in the beginning.
The 3rd order polynomial is S3(x)=(3/PI)*x-(4/PI^3)*(x^3) or S3(z)=(1/2)*z*(3-z^2) with z=x/(1/(2*PI))
I tried an Excel sheet for this function and I compared with sin() from Excel.
Either I make a mistake or the approximation error is too big.
Here is the Excel: 
Could you help to debug this?
I have a report I created that shows how many items we shipped on time, early and late. I am trying to find out the percentage of on time.

So for example the totals at the end of the report come out to  92 early 81 on time and 53 late.  What would the formula be to figure out the total percentage of on time (early counts as on time as well)?

Any help would be appreciated!
I am recreating a project I did over 20 years ago to calculate the mandelbrot set.  The code I have written is very simple yet is behaving strangely in two ways:

1) Where I have put in the statusLabel.text = "Working" - it does not change the value on screen.  Even if I put a sleep command in after the change, it still remains at the original value.

2) At the moment, the program will draw a block of orange pixels (haven't figured out the mathematics yet) but only if the Console.WriteLine commands are there.  If I comment them out, not a single pixel is drawn.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Threading;

namespace Mandelbrot3
    public partial class Mandelbrot : Form
        public Mandelbrot()
            statusLabel.Text = "Ready";

        private void goButton_Click(object sender, EventArgs e)
            int Width = 320, Height = 160, x, y, n;

            Bitmap b = new Bitmap(Width, Height);
            mandelbrotPanel.BackgroundImage = (Image)b;

            double MinRe = -2.0;
            double MaxRe = 1.0;
            double MinIM = -1.2;
            double MaxIM = MinIM + (MaxRe - MinRe)*Height / (this.Width);
            double ReFactor = (MaxRe - …
We are using TC29x Microcontroller. The flash size is 6Mbytes. There are Three banks, 2Mbyte each.

Program Flash 0 (PF0) is bank 1. Program Flash 1 (PF1) is bank 2. Program Flash 2 (PF2) is bank 3.

 PF0 address range is: 0x8000 0000 - 0x801F FFFF
 PF1 address range is: 0x8020 0000 - 0x803F FFFF
 PF2 address range is: 0x8040 0000 - 0x805F FFFF

 Where is Program Flash ECC stored. Is it within 6Mbyte ? Or is there additional storage space for ECC that we don't have access to ?

 How does Flash ECC work ? For how many bytes of data, how many bytes of ECC are there ? Whenever we write to flash, ECC updates? When we erase flash ECC updates?

 How is it possible to create Flash ECC Error ? Because everytime you write or erase flash, ECC will update?
The above was gifted. what would be most ideal specifications to aim for this (for elec wire to go with this for outdoor use)? when searching for outdoor electrical wire, below are specs are needed to be filtered thru.. can you guide how you would choose in the below availability..

Cable/Wire Type: Thermostat Wire,UF-B
Guage: /10/12/14
Conductor: 2/3
Allowed Amp: 15/20/30/50
Solid or Stranded

ideally, more durable to last a few years. (mainly for summer, and possible little snow blower too)
also ideal to have feature to roll it up when not in use
In a class of 40 students, everyone has either a pierced nose or a pierced ear. The professor asks everyone with a pierced nose to raise his or her hand. Nine hands go up. Then the professor asked everyone with a pierced ear to do likewise. This time there are 33 hands raised. How many students have piercings both on their ears and their noses?
Given the following definition, compute Q(5).
Q(n) =

0      if n = 0
1      if n = 1
3      if n = 2
Q(n − 1) + Q(n − 2) + Q(n − 3)        if n > 2
Q(5) =
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One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

I'm in the Business Intelligence Department, but practically speaking we're the Reporting Department, your basic operational type of reports - lists, lists, and more lists.

I'm at an institution of higher learning, and a new project has come up for the Math Department. They want to know relationships between courses, grades, etc.


- if someone gets a D in Calc I, what's the likelihood of graduation?  with various permutations, like taking Calc I again
- what's the likelihood of someone getting a D in Calc I, getting a D or F in Calc II
- for placing incoming students in Pre-Calc or Calc I, what are the factors that indicate success? such as Verbal SAT

So I think I've targeted the right discipline (Analytics), but not sure where to take this project.
For a birthday gift for a teen aspiring to put canon camera to good use for scenic photography and also making summer business of taking family portraits, what would be ideal camera lens to gift?

already in procession: 55-250 and 18-55.

any technical ideas on what to consider would be appreciated
Dear experts,

I am reading Functions and Graphs in Mathematics.

In order to draw all the polynomial equations (f(x)=x^2 +7x+12) I am looking at excel based formulae (linking to the graph).

What i am looking at is for excel which can handle input and provide the Y value and also draw the graph. In addition I should be able to overlay it shifts/compression and expansion.

Kindly help

LIKE  4635
Hi Experts,

I was assigned to set up passwords to our users in a way that

1- Each user/department has their own password.
2- It should auto get changed every 3 months.

I was thinking of the following..

Since we have a table containing all users initials (AA, BA, CW..), so the password should be a logic that has both their initial, current year and yearly quarter as part of the password, however it should also contain some logic that users should not figure out that the password is indeed based on those specific info?

What are your thoughts?
I have Comcast. 20Mbs up/150Mbps down. I essentially want to know how much I can upload and download per hour. I come up with roughly 9GB upload per hour and then 62GB download per hour. Of course that is theoretical. Is my math correct?
I have an iPhone 6 and hope to find an app or combination of tools to I can use to estimate distance and direction of objects (buildings) that are a mile or three away from me.

given the phone knows its location and orientation, might it be used w/ the camera to plot the location of the object I focus in on?

What's the easiest way to do this? I do not need precision, but just a pretty good estimate.

I know that a circle has 360 degrees and Pi has a very specific an known value.

The question is, must a circle had 360 degrees? Or was that a decision that was made so each quarter would have 90 degrees?

So, was Pi "backed into"?

If Euclid had wanted a circle to be 400 degrees, could he have simply used a different formula to generate Pi?


And what is that formula to generate Pi, if you have it.

2 groups of people need to vote yes/no on a subject.
The subject does not relate to the group they are in and so the voting is seen as independent with both groups having the same information available to make a decision.

One group of 40 votes 50% yes and 50% no.

How do I calculate the odds of the other group of 58 voting 100% no given the vote of the other group.
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I have used Python, Natural Language Processing and web scraping technology to do some deep mining of Google's vast warehouses of articles on the web.

Is what I described considered artificial intelligence?

Or, in order to satisfy the requirement of AI must that model also automatically adjust it's algorithms based on the results of the searches? In my case, the adjustments were manual.


Can you please suggest me any good book or links on this topic?

Please find attached the excel spreadsheet.

You will find two sheets.  Tarif and Table.

In the Tarif sheet, I need to add the weight and the Zone Number, so that in B2, I get the Tarif.

I put an example of a tariff in the tariff sheet.

In that example, the weight is higher than 24 and lower than 50, and in zone 2.  The expected calculated tariff is, therefore,  $11.

I need to make a formula that will calculate the tariff automatically.

Thanks for your help,
Consider a typical Automotive Embedded  Software System.  

A discrete input signal is 0 or 1.  An example of discrete input is ignition ON or OFF.

After discrete input signal is debounced or a state change is latched, is discrete input signal still raw value?

Second question:   Should Electronic Control Unit (ECU) low level software debounce discrete inputs or just read the real time state of discrete input?  Are there any exceptions meaning some discrete inputs should be debounced, whereas others don't need to be debounced?
there are too many cap options in,
 can you recommend what would be practically and also 'technology' wise (make material, construction, concept) best suited for a Teen boy
 who is going to travel to a very hot (sunny) region for a few  weeks program in summer.
 thanks for any ideas.

I'm having an algebraic brain fart over here.  How would I solve for variable K in the following equation:

.25(2√K) - .03K = 0

I can move the .03K to the right of the equality symbol and square both sides but then I'm a bit fuzzy after that.  It's been a while.

Thanks for your assistance

Math / Science




Articles & Videos



The Math / Science topic primarily includes discussions of mathematics, physics, statistics and economic analysis, but also biology, chemistry and other sciences.