The possibility of stating the second law of thermodynamics in terms of the increasing behaviour of a physical property establishes a connection between that branch of physics and the theory of algebraic inequalities. We use this connection to show how some well-known inequalities, such as the standard bounds for the logarithmic function or generalizations of Bernoulli's inequality, can be derived by thermodynamic methods. Additionally, we show that by comparing the global entropy production in processes implemented with decreasing levels of irreversibility but subject to the same change of state of one particular system, we can find progressively better bounds for the real function that represents the entropy variation of the system. As an application, some new families of bounds for the function log ( 1 + x ) are obtained by this method.

1.
E. R.
Love
, “
Some logarithm inequalities
,”
Math. Gazette
64
,
55
57
(
1980
).
2.
F.
Topsok
, “
Some bounds for the logarithmic function
,”
Inequality Theory and Applications
(
Nova Science Publishers
,
New York
,
2007
), Vol. 4,
137
151
3.
C.
Chesneau
and
Y. J.
Bagul
, “
New sharp bounds for the logarithmic function
,”
Electron. J. Math. Anal. Applicat.
8
(
1
),
140
145
(
2020
).
4.
P. G.
Tait
, “
Physical proof that the geometric mean of any number of quantities is less than the arithmetic mean
,”
Proc. Roy. Soc. Ed.
6
,
309
(
1868
); reprinted in Sci. Papers 1, 83 (1898).
5.
A.
Sommerfeld
,
Thermodynamics and Statistical Mechanics
(
Academic Press
,
New York
,
1964
).
6.
E. D.
Cashwell
and
C. J.
Everett
, “
The means of order t and the laws of thermodynamics
,”
Am. Math. Mon.
74
,
271
274
(
1967
).
7.
P. T.
Landsberg
, “
A thermodynamic proof of the inequality between arithmetic and geometric means
,”
Phys. Lett. A
67
,
1
(
1978
).
8.
R. J.
Tykodi
, “
Using model systems to demonstrate instances of mathematical inequalities
,”
Am. J. Phys.
64
(
5
),
644
648
(
1996
).
9.
L.
Wang
, “
Second law of thermodynamics and arithmetic-mean-geometric-mean inequality
,”
Internat. J. Mod. Phys. B
13
(
21–22
),
2791
2793
(
1999
).
10.
C.
Graham
and
T.
Tokieda
, “
An entropy proof of the arithmetic mean-geometric mean inequality
,”
Am. Math. Mon.
127
(
6
),
545
546
(
2020
).
11.
R. S.
Johal
, “
Optimal performance of heat engines with a finite source or sink and inequalities between means
,”
Phys. Rev. E
94
,
012123
(
2016
).
12.
Y.-C.
Li
and
C.-C.
Yeh
, “
Some equivalent forms of Bernoulli's inequality: A survey
,”
Appl. Math.
4
(
7), 1070
1093
(
2013
).
13.
C. E.
Mungan
, “
Damped oscillations of a frictionless piston in an adiabatic cylinder enclosing an ideal gas
,”
Eur. J. Phys.
38
,
035102
(
2017
).
14.
See supplementary material at https://www.scitation.org/doi/suppl/10.1119/5.0121919 for a simple proof that the introduction of an intermediate reservoir diminishes the global entropy production, and for the details of the derivation of the generalized Bernoulli's inequality.
15.
P.
Abriata
, “
Comment on a thermodynamical proof of the inequality between arithmetic and geometric mean
,”
Phys. Lett. A
71
,
309
310
(
1979
).
16.
M. A. B.
Deakin
and
G. J.
Troup
, “
The logical status of thermodynamic proofs of mathematical theorems
,”
Phys. Lett. A
83
(
6
),
239
240
(
1981
).
17.
S. S.
Sidhu
, “
On thermodynamic proof of mathematical results
,”
Phys. Lett. A
76
,
107
108
(
1980
).

Supplementary Material

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