Ian If I understand properly you know %co2 and you want to know x right ? Therefore you just have to solve the equation. It's a pure math problem, no a LV one. Let's rename your equation %CO2=(((3.10933*(X*X))+(.5602*X)))/(0.30204-X) like so y=(ax*x+bx)/(c-x) <=> y(c-x)=(ax*x+bx) <=> ax*x+(b+y)x-yc=0 Then assuming than D=(b+y)*(b+y)+4yac is positif you have the following: x=[-b+(or-)Sqr(D)]/2a
Note: double check that result as I have not solve such equation in a long time PJM --- Ian Lloyd <[EMAIL PROTECTED]> wrote: > Dear all > > I would appreciate some help with a maths equation > problem I have. > > I am writing some software to test our IRcels, these > are infra red gas detection sensors used to detect > CO2 or hydrocarbons eg pentane. > > For the test I have to calculate the standard > fractional absorbance(X) of the test gas from the > following equation. > > %CO2=(((3.10933*(X*X))+(.5602*X)))/(0.30204-X) > > For a gas bottle of 2%CO2 I have been given a value > of 0.19144 for X so far so good. Plug a value of > 0.19144 into the equation and you will get a > solution of 1.99999 > > In reality the gas concentration would not be 2.00 > it would probably be 2.05 for example therefore I > have to use the equation in an iterative manner, > modifying the value of X each time until the > solution = 2.05 > > I have tried changing the value of X by the > percentage difference the solution is away from the > required solution but this results in under shooting > then overshooting the required solution in larger > and larger jumps. > > Can anybody recommend any of the maths functions in > labview or just point me in the right direction as > maths was never my strongest subject. > > I am using LV 7.1 on windows 2000 > > Thanks for any help > > > > > > Ian Lloyd > Extn 304 > Direct number 023 92288140 > > > > _____________________________________________________________________ > This message is intended solely for the use of the > individual or organisation to whom it is addressed. > It may contain privileged or confidential > information. If you have received this message in > error, please delete accordingly. If you are not > the intended recipient, you should not use, copy, > alter, or disclose the contents of this message. > All information or opinions expressed in this > message and/or any attachments are those of the > author and are not necessarily those of City > Technology Ltd. > > City Technology Ltd accepts no responsibility for > the loss or damage arising from its use, including > damage from virus. > _____________________________________________________________________ > This message has been checked for all known viruses > by UUNET delivered > through the MessageLabs Virus Control Centre. For > further information visit > http://www.uk.uu.net/products/security/virus/ > __________________________________ Do you Yahoo!? Friends. Fun. Try the all-new Yahoo! Messenger. http://messenger.yahoo.com/
