The first T-ds relation reduces to Tds = pdv if the internal energy remains constant. Use the

Question:

The first T-ds relation reduces to Tds = pdv if the internal energy remains constant. Use the PC system state daemon to evaluate the state of steam at 100 kPa and 200oC. Also evaluate two neighboring states at 99 kPa and 101 kPa, holding internal energy constant and compare the two sides of the equation. Why don't the two sides match exactly?