Solving bridge equation

[Vindhyachal.takniki]

1. I am using wheatstone bridge to measure change in resistance.
2. Bridge is excited by IDAC instead of voltage source.
3. I have made a equation for it in term of voltage output versus change in resistance. It is attached with circuit in pdf.
4. Can anyone check if it ok.
5. I have simulated the results with my equations & they are ok.