Error Definition and 998 Threads

Hi, I am especially writing this, because there is no specific explanation I found online. I checked the BCs and other variables, but could not find any mistakes. I am working on a semiconductor device that is basically n-doped homogeneously, has sizes 50um-15nm, and with a drain voltage 1V...

Homework Statement In a flame test lab, where different unknown substances are heated and the identity of the substance is determined by the color emitted, what can be some sources of error? Homework Equations n/a The Attempt at a Solution I need three sources of error, and so far I have...

I'm having a physics lab in which a report needs to be submitted after an experiment. The experiment includes many measurements: values with their errors. I need to round the error up to 2 significant digits, and then to round the value up to to the amount of digits that the error is presented...

Homework Statement Hello, I've been using a light spectrometer to try to measure the reflectance of a sample of a protein I have on a glass slide. I followed the manual's instructions and first took a dark spectrum and a reference spectrum. However, the intensity was too high (far above the...

In this homework question we are told to calculate the half-life of an isotope based on count-rates before and after a given time interval, the relevant equation is given below. Half-life = t1/2 = tln(2)/ln (A/A0) The second part asks to determine the standard deviation of the half-life due...

Consider two functions f, g that take on values at t=0, t=1, t=2. Then the total error between them is: total error = mod(f(0)-g(0)) + mod(f(1)-g(1)) + mod(f(2)-g(2)) where mod is short for module. This seems reasonable enough. Now, consider the two functions to be continuous on [0,2]. What...

I tried posting this question in this forum a couple of weeks ago, but didn't get an answer to my question. I'm going to try posting it again using the formatting template so that it is hopefully clearer. I am also not sure if this is the right forum to be posting this in. It is a problem I ran...

In physics lab course I measured equivalence conductivity of NaCl in infinite dilution Λ0 as a function of temperature T. So I have observations (T, Λ0) and fitted a line using the least squares method in Ms excel (lol :oldbiggrin:). The formula of the line is Λ0(T)=c0+c1T, where c0 and c1 are...

Homework Statement From extensive records it is known that the duration of treating a disease by a standard therapy has a mean of 15 days. It is claimed that a new therapy can reduce the treatment time. To test this claim, the new therapy is to be tried on 70 patients and their times to recovery...

Homework Statement I am writing a lab report and I need to calculate the uncertainty error for Gravitational Potential Energy and Kinetic Energy. The Professor told us that the margin of uncertainty for time is +- 0.025 seconds, margin for height is +- 0.001 meters, margin for mass is +-0.001...

Homework Statement Hello! In our class, we just completed a lab on momentum and energy conservation in collisions. It was a computer simulation. Although, for the lab report, the teacher wants us to write the random, systematic, and human errors. Can someone describe what each error means? What...

The program must calculate the length of the curve of ƒ=3.1*x^2-5.3/x between x=1/2 and x=3/2.The legth should be calculated as the sum of n line segments starting with n=1 and ending with n=20. I really can't find why the result I'm getting is wrong.Thanks in advance I am giving you the code...

Homework Statement My best fit-line for my average velocity time graph doesn't seem to start at 0 m/s. I have no idea how to explain this in my conclusion - http://imgur.com/zniGGkw. This lab was conducted by using a recording timer, and a mass. We started the recording timer first, then let...

Hi folks, apologies if this is in the wrong forum. I'm a new undergrad physics student and I'm having trouble figuring out how to 'do' error analysis. (I had a quick look through some similar posts here & am still none the wiser.) I'll use my recent lab experiment on Resonance in a Tube as an...

Hi, I am trying to find the error propagated by calculating the sum of a set of mass flow rates collected over the same length of time. The sum of mass flow rates can be calculated with two approaches, since the collection time is the same for all of them. Approach (1) is adding up all of the...

Hello! (Wave) I have written the following code in matlab: function v=uexact(x,t) v=sin(2*pi*x)*exp(-4*pi^2*t); end function [ex]=test3 h = 1/50; T=1/2500; x=0:h:1; t=0:T:1; ex=uexact(x,t); end I...

So I just did a lab on resonant frequency, and have to find the error of the period: $$T = 2π\sqrt{m/k}$$ m and k were measured with an error of Δm and Δk. My teacher didn't explain well how to do errors, so I just want to know if I did this right. Prorogation of Error equations: $$y=x^n ⇒...

I am checking the accuracy of my speedometer. When my speedo says I'm doing 100km/h, I record an actual speed of 123km/h. When my speedo says I'm doing 60km/h, I record an actual speed of 68km/h. I have more data but it corroborates this simple example: error increases with increasing speed. I...

Homework Statement Based on Microdosimetry theory, trying to figure out error propagation for a lot of quantities that are produced from radiation spectra. I am having trouble finding information on how to calculate and propagate errors when the quantities in my equations are not independent...

Homework Statement f(x,y) = (xy) / (x2 + y4), when (x, y) ≠ (0,0) 0, when (x,y) = (0,0) Homework Equations Explicitly show that f(x,y) does not satisfy lim h -> 0 [ E(v,h) / ||h|| ] = 0 when v = 0 (h, v, and 0 are all vectors; I'm not sure how to put a hat on them) The Attempt at a Solution I...

So, I was making this simple image processing programming for the bitmap image. Like the image I upload here, that Thread 1: EXC_BAD_ACCESS occurred although the program can perfectly running when I run it on Mac Terminal and on Windows. What seems to be the problem? Since my English is not my...

Homework Statement I have a few data-analysis problems due to Thursday, 1. Assume that a sandbag is dropped at different heights and the observations are (z i;ti) pairs. Physical model for a free fall is z=½gt2. Assume that the height measurement z has an additive random error v. The...

Hi, I try to write program to calculating mach number, with using bisection method. When I run program, fortran write to me an error in line 40. Can you help? I tried to calculating function by using wolfram sucesfully but I need to run it on fortran, An equation is 1.7795 - (0.334898 (1 + 0.2...

Homework Statement So I've done an experiment by scanning over a range of angle and measuring the intensity of X-Rays. There are peaks where I have X-Ray diffraction occurring and in order to do analysis I need to identify the values of angle and an error (as in the plus/minus) on this value...

Homework Statement Simplify: 1/k [(k-1) x_n+ x^k/(x_n^(k-1) )]- 1/k [(k-1)x+ x^k/x^(k-1) ] where e_n = x_n - x x_n means x subscript n e_n means e subscript n It might be easier to look at the picture I typed out in MS Word...

Hi PF! Can anyone tell me what you think the best method is to calculate the % error between two curves? My thoughts were to take $$100\frac{ \sqrt{\int_a^b (f-g)^2 \, dx}}{\int_s f \, ds}$$ where the integral in the denominator is a line integral. What are your thoughts? Thanks for looking!

My program says it doesn't recognise the symbol signum(double) or sqrt(double)! I have definitely done the whole import java.lang.Math; thing. And signum and sqrt aren't symbols anyway. Is that too vague? I can post the actual code. It's only my second week learning java, so it's supposed to be...

I am using fortran 90 to find the prime numbers (1-100). When I print to the console, everything works. If I try to write to an text file (.out). This is from my command line: Sues-MacBook-Air:FORTRAN sueparks$ gfortran PRIME.f90 Sues-MacBook-Air:FORTRAN sueparks$ ./MY_PRIME.out PROGRAM PRIME...

Homework Statement differentiate ∫ e^(-x*t^4)dt from -x to x with respect to x.[/B]Homework Equations erf(x) = (2/sqrt(π)) ∫e^(-t^2)dt from 0 to x. Leibniz rule. I know that ∫t^2e^(-t^2)dt from 0 to x = (√π/4)*erf(x) - (1/2)*x*e^(-x^2)[/B]The Attempt at a Solution By using Leibniz rule...

Homework Statement Homework Equations Doesn't the integral of sec x tan x equal sec x? The Attempt at a Solution

Homework Statement Ok, so suppose I have an equation like V_out = 0.5(1 + R4/R3)(V1+V2) and I know the R3 and R4 has a tolerance of +-5%. For such an equation and similar ones, how would I estimate the possible range of values V_out? For example, I'd like to find out something like...

I had a question about how to properly perform error analysis on a series of distance measurements. I need to find the relative error in the distance. I was wondering, should I use the instrument uncertainty divided by the measurement (in this case, it would be 0.005m / (mean measurement)). Or...

Homework Statement Suppose you measure three numbers as follows: Homework Equations x= 200. +-2. y= 50. +-2. z= 40. +-2. where the three uncertainties are independent and random. Use step-by-step propagation to find the quantity q= x/(y-z) with its uncertainty. The Attempt at a...

For the error bound for taylor's theorem, for the n+1 derivative evaluated at some c which maximizes the derivative my textbook says c must be between a and x..but today my teacher said that c must be between absolute value x and negative absolute value x, which is different than I thought. An...

I am programming in Eclipse and I keep seeing the error " Type mismatch: cannot convert from int to String", not only in the example I am going to provide but other programs. I've just started programming in Java. Could someone explain to me what this error exactly means? publicclassPracOne{...

I had a student calculate ##\tan\left(\frac{5\pi}{6}\right)## on a TI-84 calculator and he had a rounding error in the 6th or 7th decimal place. This isn't really a big deal, but he asked and we quickly found out it was because he was in fraction display mode. I don't know too much about...

Okay so I was integrating an expression and ended up getting an imaginary error function in the answer. I'm not sure where to go from there, I plugged it into wolfram and the root it gave me looks nice but is that worth anything to me? The integral was being evaluated from -∞ to ∞, would I need...

Hello, I have a question asking me to find the volume of a rectangular prism. The dimensions are as follows: x = 20 ± 0.2 cm, y = 30 ± 0.2 cm, z = 70 ± 0.4 cm I am asked to report the answer with the correct number of significant figures and include the error. What I have so far: V = xyz =...

Homework Statement I need to find three potential reasons for my .5% error in a lab where I used the Archimedes Principle to measure the density of Iron. We only used a graduated cylinder full of water and an iron mass. I measured the water level from the meniscus. We used two different...

According to Wikipedia, Cavendish was able to measure a force of 1.74E-7 N or “roughly the weight of a large grain of sand[13] of 0.13 mg” However, with my calculations using m=F/g, where g=9.81m/s/s Gives m=1.74E-7/9.81 = 1.77E-8 kg = 0.0177 mg Which is much less than 0.13 mg Am I missing...

hi PF! I've attached pictures to help you all see what is happening. Basically, I am running a forward time-centered space finite difference scheme, which is $${h_i^{j+1} \approx \left[ h_i^j \left( \frac{h_{i+1}^j-2h_i^j+h_{i-1}^j}{\Delta z^2} \right) + \frac{1}{2}\left(...

Find the error in the following argument by providing a counterexample. “The reflexive property is redundant in the axioms for an equivalence relation. If x ∼ y, then y ∼ x by the symmetric property. Using the transitive property, we can deduce that x ∼ x.”

Dear all, I am working on Arduino and try to upload to Teensy, but when I uploaded, I had a problem with this message, "Interface22.ino:32:21: fatal error: MCP4725.h: No such file or directory compilation terminated. Error compiling"Could you please help for the reason and how to solve this...

I got and fatal error like below. " fatal error. continue run not yet consistent with histp writing. " Couldn't I use continue run when I make histp file? please, help me... calculation time is too long, so I want to use continue run.

Homework Statement Three charged particles are placed at each of three corners of an equilateral triangle whose sides are of length 2.7 cm . Two of the particles have a negative charge: q1 = -6.0 nC and q2 = -12.0 nC. The remaining particle has a positive charge, q3= 8.0 nC . What is the net...

Homework Statement I have make a program that solves the distance between 2 points on a triangle. Homework Equations none The Attempt at a Solution /* homework 1 */ #include <stdio.h> #include <math.h> int main(void) { // Declare and initialize variables float x1=1, y1=5, x2=4, y2=7...

I'm doing a lab where we use three strings connected to a ring, with each string attached to separate spring scales. What would be sources of error in this? And how does friction affect my results?

When I switched on my laptop yesterday, a window opened automatically with a name : "C:\Windows\system32\Cscript.exe". It now happens every time I restart my laptop. Is this because of some computer virus or should I just ignore it ? (My laptop is 5 years old and runs on Windows 7 ultimate 32...

(Sorry if this is the wrong place for this question, I wasn't sure where to put it) I've been running an experiment with rabbits, and am trying to figure out the error of my feed measurement. I fed them using a 1/3 cup measure, and recorded the number of scoops they got. I estimated that the...

I've been working an internship over the summer, and I ran into a very humorous coding error. Everyone at the office got a kick out of it, and I thought some forum members might laugh at it as well: So painful! It was not very funny fixing it though.