Math / Science

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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Does any one knows a web site where can I practice the nomenclatures?
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Can someone help with this?

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Let p = 4x - 7

Is the below equation equivalent to (4x−7)^2 + 16 = 40x - 70 in terms of p ?

p^2​​ −10p+16=0
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If I raise a number to the power of five the last digit of the result is always the same as the last digit of the number with which I started.  For example  7^5 = 16807.  The last digit of both numbers is a five.
Are there any rules regarding when the last 2 digits are repeated?  For example 25 is always repeated.  I don't think 12 is ever repeated.
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How can I solve these kind of problems in my brain without using pencil and calculator?

2.3*10^7*5.2*10^-5/4.3*10^2
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I have the Excel file below with 3 columns.
On one row I have a pair of q, k corresponding to a certain x.
In the sheet are different values for x.
I need to find what pairs of q, k are common for all values of x.
How do you do that fast and easy?
Pairs.xlsx
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What is the best and easiest approach, method, software to solve a system like the one below?

1=1*(3.14*2^p-1*1*[(23.14-5)*2^q-1*1*(3.14-3)/2^k]/2^r)/2^s
3=8*(3.14*2^p-8*8*[(23.14-5)*2^q-8*8*(3.14-3)/2^k]/2^r)/2^s
50=128*(3.14*2^p-128*128*[(23.14-5)*2^q-128*128*(3.14-3)/2^k]/2^r)/2^s
2896=8192*(3.14*2^p-8192*8192*[(23.14-5)*2^q-8192*8192*(3.14-3)/2^k]/2^r)/2^s
4096=16384*(3.14*2^p-16384*16384*[(23.14-5)*2^q-16384*16384*(3.14-3)/2^k]/2^r)/2^s

Could you help to find a set of solutions? I guess are more than one.
This is not homework, but rather one of that engineering approximation problem that ended up in a set of unknown variables.

Basically the function is.
S5(x)=x*(PI*2^p-x*x*[(2PI-5)*2^q-x*x*(PI-3)/2^k]/2^r)/2^s
with p, q, k, r, s unknown.
And next known set of solutions with 1 digit approximation allowed for S5x:
x - S5x
1 - 0
2 - 1
4 - 2
8 - 3
16 - 6
32 - 13
64 - 25
128 - 50
256 - 101
512 - 201
1024 - 401
2048 - 799
4096 - 1567
8192 - 2896
16384 - 4096
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Can you please tell me if the calculations are correct?
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Hi,
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;
  clc;
  syms x y 
  y = -x; 
  z=int(y,x);
  v=[0:0.1/19:0.1];
  dr=0.1/20;
  for i=1:20
      x=v(i);  
      kk(i)=eval(y)*(dr);    
  end
  R1=sum(kk(1,:));
  x=0.1;
  z1=eval(z);
  x=0;
  z2=eval(z);
  R2=z2-z1;

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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?

https://en.wikipedia.org/wiki/Prism#/media/File:Light_dispersion_conceptual_waves.gif

Thanks
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What does it mean to be "Always On"?
LVL 4
What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

Which is the strongest base for an antacid which works the quickest and is the most effective?
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a car travels 100km in 50 minutes.what will the speed be in km\h
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I would like to implement a fast fixed point sine approximation for PIC24F microcontrollers on 16bit.
I started from here: http://www.coranac.com/2009/07/sines/
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: https://goo.gl/2KJXj8 
Could you help to debug this?
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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!
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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()
        {
            InitializeComponent();
            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 - …
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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?
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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
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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?
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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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Industry Leaders: We Want Your Opinion!
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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.

Examples:

- 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.
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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
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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
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HOW MANY PAIR COMBINATIONS CAN BE FROM AN 4 NUMBER

LIKE  4635
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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?
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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?
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Math / Science

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