How to Calculate Uncertainty in Complex Equations with Trigonometric Functions

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Homework Help Overview

The discussion revolves around calculating uncertainty in a complex equation involving trigonometric functions, specifically focusing on the equation for R, which incorporates sine and cosine functions along with square roots. The original poster expresses difficulty in applying basic uncertainty rules to this more complicated scenario.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the need for understanding partial derivatives to calculate uncertainty in the given equation. Some question whether the uncertainty can be derived solely from the partial derivative of the equation.

Discussion Status

The discussion is ongoing, with some participants providing guidance on the use of partial derivatives. There is a mix of familiarity with the concepts, as some participants express confidence while others seek clarification on the application of these mathematical tools.

Contextual Notes

The original poster mentions using Excel for calculations, which may influence the methods discussed. There is also an indication of limited prior knowledge regarding differentials and advanced uncertainty calculations.

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calculating uncertainty
I have a lab where I have to calculate the theoretical value of R using the following equation and then find the uncertainty in R.

R=(xCOS(y))*((-xSIN(y)-SQRT((xSIN(y))^2-2*-9.8*z))/-9.8)
*I know the values of x,y,z and their respective uncertainties.

The problem is that we have only learned basic uncertainty rules (i.e. for multiplication/division you add the %uncertainty, for addition/subtraction you add the absolute uncertainties). This is much more complicated since I have to deal with SIN/COS and square roots. I was searching around and it seems that I have to calculate the partial derivative or differentials. I am not familiar with differentials and I have no idea how to solve this problem. If anyone can offer any help whatsoever it would be greatly appreciated or anywhere where I can find this information.

i'm using excel if that makes any difference.
 
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Do you know how to calculate a derivative? If so, it shouldn't take more than a minute to learn how to take a partial derivative.
 
take extremes!
simple and perfect
 
i know how do to partial derivatives but is the uncertainty just the partial derivative of the equation.
 

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