I'm sending you a VI (privately) that solves your problem iteratively. It uses the approach of successive approximation.
===============Original Post====================================== 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. =============================================================== Lewis Drake Process Automation Corporation Belle Mead, NJ 908 359-1011 www.processauto.com
