Google Answers Logo
View Question
 
Q: Tough Calculus Integration Problem ( No Answer,   1 Comment )
Question  
Subject: Tough Calculus Integration Problem
Category: Science > Math
Asked by: spoonman-ga
List Price: $100.00
Posted: 13 Jul 2006 12:22 PDT
Expires: 12 Aug 2006 12:22 PDT
Question ID: 746028
I would like to integrate the following equation. It is a chemical
rate equation (Arrhenius) where I have temperature & relative humidity
as functions of time. Both are sinusoidal, reflecting a typical yearly
climate:
e^-(Integral(k*RH(t))dt), where k=Ae^-(E/R*T(t)) and
RH(t) = 0.7+0.1*Sin(0.01t), T(t) = 300+4.5*Sin(0.01t).

Request for Question Clarification by hedgie-ga on 20 Jul 2006 08:25 PDT
It is fairly simple to integrate that numerically. 
Do you want help with that as an answer?

Or does 'integrate' means :find an analytical solution (which does not exist)?

Clarification of Question by spoonman-ga on 31 Jul 2006 09:47 PDT
In response to hedgie-ga, I was hoping to arrive at an equation which
I could then graph to show the reaction rate as a function of time
(given the input temperature, and relative humidity equations).

Sorry, I don't understand what you mean by integrate numberically?
Does this mean that you would achieve a numerical result given
integration limits? If so, that's not of particular use to me.

Request for Question Clarification by hedgie-ga on 31 Jul 2006 11:20 PDT
In numerical solution you do not obtain an equation, but rather a table

You can still plot it vs time.


http://www.myphysicslab.com/numerical_vs_analytic.html

most  diff. eq. of the type you have do not usually have an analytical solution.
Answer  
There is no answer at this time.

Comments  
Subject: Re: Tough Calculus Integration Problem
From: cw4ever-ga on 17 Jul 2006 11:17 PDT
 
As a matter of significance, you ought to be able to take T(t) = 300. 
That is, given your numerical constants, your solution will only have
one significant digit anyway.

Letting T(t) = 300 yields:  exp[-A*exp(-E/(300*R))*(0.7*t-10*cos(0.01t))]

If this is unacceptable, there are other approximations you may be
able to make.  However, I doubt it can be solved exactly.

Important Disclaimer: Answers and comments provided on Google Answers are general information, and are not intended to substitute for informed professional medical, psychiatric, psychological, tax, legal, investment, accounting, or other professional advice. Google does not endorse, and expressly disclaims liability for any product, manufacturer, distributor, service or service provider mentioned or any opinion expressed in answers or comments. Please read carefully the Google Answers Terms of Service.

If you feel that you have found inappropriate content, please let us know by emailing us at answers-support@google.com with the question ID listed above. Thank you.
Search Google Answers for
Google Answers  


Google Home - Answers FAQ - Terms of Service - Privacy Policy