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# Solving a system of exponential equations

## Solving a system of exponential equations

(OP)
Hello,

I'm trying to solve in Matlab a system of three exponential equations that I have successfully solved in MathCAD. However, I am not able to find a good solution in Matlab (see the attached file). I have tried to get one solution of two equations fixing one of the three variables and then numerically find the third one by fzero, but the precision that I get is far away from MatchCAD's solution (I need at least 8 correct decimals so my CAD software doesn't complain).

The only unknowns are Ky, dx and tangslope, and the exact solutions are 0.032174329260391681608, 0.092798905026180063372 and 0.12086575209254294237 respectively, for the inputs x1=0.07, x2=0.1155, y1=0.03465 and y2=0.055. If there is more than one solution, the correct solution sould have a Ky value slightly lower but close to y1. I have also tried using numeric::solve but I cannot get it to work for the three equations.

Merry Christmas and thanks in advance.

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