Can anyone give me the equation for the second law of thermodynamics...
There is no straight equation for 'the second law of thermo'.
There is an equation for entropy (there are acutally quite a few eq for entropy).
The second law tells you that entropy will always increase in a closed system.
Is there any specific question you have concerning the 2nd law, as what you asked could have been very easily found using google.
This, I guess, is an equivalence, not an equation.
Also, note that this is for an isolated system.
Cheers Pythagorean.... lovely xxChrisxx.
Separate names with a comma.