Hello Guys,
I can't understand some parts of the MOSFET static characteristics curve. Here the equation given for the Triode region for the characteristics curve of the MOSFET is VP≤ VGS ≤ 0 and
VDS ≤ VGS-VP. My question is How I can find these two equations by looking at the graph? Or it would be better if someone could explain how to determine these two equations by analyzing the graph shown in the picture.

 

The characteristics look like they are for a depletion mode device or a JFET. The more common implementation is for an enhancement mode device. You can find a better development of the characteristic equations from a source like:

Brunn, CMOS Integrated Circuit Simulation with LTspice
LTspice@groups.io | CMOS Integrated Circuit Simulation with LTspice - free book download

 

How I can find these two equations by looking at the graph?

Those equations were likely derived from the solid-state physics of the device, not it's operational characteristics.