EUROPEAN JOURNAL OF PURE AND APPLIED MATHEMATICS Vol. 14, No. 3, 2021, 723-736 ISSN 1307-5543 – ejpam.com Published by New York Business Global Note on a Stieltjes transform in terms of the Lerch function Robert Reynolds1,∗, Allan Stauffer1 1 Department of Mathematics and Statistics, Faculty of Science, York University, Toronto, Ontario, Canada Abstract. In this work the authors derive the Stieltjes transform of the logarithmic function in terms of the Lerch function. This transform is used to derive closed form solutions involving fundamental constants and special functions. Specifically we derive the definite integral given by∫ ∞ 0 (1− bx)m logk(c(1− bx)) + (bx+ 1)m logk(c(bx+ 1)) a+ x2 dx where a, b, c,m and k are general complex numbers subject to the restrictions given in connection with the formulas. 2020 Mathematics Subject Classifications: 01A55, 11M06, 11M35, 30-02, 30D10, 30D30, 30E20 Key Words and Phrases: Stieltjes transform | Lerch | Definite integral | entries in Gradshteyn and Rhyzik 1. Significance Statement The Stieltjes transform and Lerch function were both developed between 1856-1922, by famous mathematicians Thomas Joannes Stieltjes and Mathias Lerch respectively. The two functions are not well documented in current literature. The Stieltjes trans- form has many real world applications such as in Cognitive Radio Communication and Networking and the Lerch function is closely related to Poisson’s summation formula. In this article we generate a new table of definite integral formulas which can be used as reference similar to current Table of definite integrals. ∗Corresponding author. DOI: https://doi.org/10.29020/nybg.ejpam.v14i3.3991 Email addresses: milver@my.yorku.ca (R. Reynolds), stauffer@yorku.ca (A. Stauffer) http://www.ejpam.com 723 © 2021 EJPAM All rights reserved. R. Reynolds, A. Stauffer / Eur. J. Pure Appl. Math, 14 (3) (2021), 723-736 724 2. Introduction n the late 1800’s Thomas Joannes Stieltjes, a Dutch mathematician found the Stielt- jes transform. In this work we will derive this formula as shown in the abstract which does not exist in current literature. We will use this definite integral to produce formal derivations of known integral formulas in [1] and [2]. We will also derive new formula which can be considered an extension to Erdeyli’s extensive table of transforms. The derivations follow the method used by us in [5], [4], [6], [7], [9] and [8]. This method involves using a form of the generalized Cauchy’s integral formula given by (1) yk k! = 1 2πi ∫ C ewy wk+1 dy. where C is in general, an open contour in the complex plane where the bilinear concomitant has the same value at the end points of the contour. Then multiply both sides by a function, then takes a definite integral of both sides. This yields a definite integral in terms of a contour integral. Then we multiply both sides of equation (1) by another function and take the infinite sum of both sides such that the contour integral of both equations are the same. 3. Definite integral of the contour integral We use the method in [9]. The variable of integration in the contour integral is z = m + w. The cut and contour are in the second quadrant of the complex z-plane. The cut approaches the origin from the interior of the second quadrant and the contour goes round the origin with zero radius and is on opposite sides of the cut. We replace y in 1 by logk(c(1 − bx)) and multiply by (1 − bx)m/(a2 + x2) in the first case and by logk(c(1 + bx)) and multiply by (1 + bx)m/(a2 + x2) in the second case and add them. The integration is over x now instead of y. (2) 1 k! ∫ ∞ 0 (1− bx)m logk(c(1− bx)) + (bx+ 1)m logk(c(bx+ 1)) a+ x2 dx = 1 2πi ∫ ∞ 0 ∫ C cww−k−1 ((1− bx)m+w + (bx+ 1)m+w) a+ x2 dwdx = 1 2πi ∫ C ∫ ∞ 0 cww−k−1 ((1− bx)m+w + (bx+ 1)m+w) a+ x2 dxdw = 1 2πi ∫ C πcww−k−1a 1 2 (m+w−1)(−b)m+w csc(π(m+ w)) ( 1 ab2 + 1 )m+w 2 sin ( 1 2 (m+ w) ( π − 2 cot−1 (√ ab ))) + πcww−k−1a 1 2 (m+w−1)bm+w csc(π(m+ w)) ( 1 ab2 + 1 )m+w 2 sin ( 1 2 (m+ w) ( 2 cot−1 (√ ab ) + π )) dw R. Reynolds, A. Stauffer / Eur. J. Pure Appl. Math, 14 (3) (2021), 723-736 725 from equations (3.227.1) and (3.227.2) in [3], using partial fractions, where Re(a) ≥ 0 and Re(m+ w) < 1. 4. The Lerch function The Lerch function has a series representation given by (3)Φ(z, s, v) = ∞∑ n=0 (v + n)−szn where |z|< 1, v 6= 0,−1, .. and is continued analytically by its integral representation given by (4) Φ(z, s, v) = 1 Γ(s) ∫ ∞ 0 ts−1e−vt 1− ze−t dt = 1 Γ(s) ∫ ∞ 0 ts−1e−(v−1)t et − z dt where Re(v) > 0, or |z|≤ 1, z 6= 1, Re(s) > 0, or z = 1, Re(s) > 1. 5. Infinite sum of the contour integral In this section we will again use Cauchy’s integral formula (1) and taking the infinite sum to derive equivalent sum representations for the contour integrals. 5.1. Derivation of the general sine contour integral Use equation (1) and replace y by y + it and multiply by emit for the first equation. Next we form the second equation by replacing t by −t and taking their difference to get (5) ie−imt ( (y − it)k − e2imt(y + it)k ) 2k! = 1 2πi ∫ C w−k−1ewy sin(t(m+ w))dw 5.2. Derivation of the contour integral In this section we will derive the contour integral given by∫ C πcww−k−1a 1 2 (m+w−1)(−b)m+w csc(π(m+ w)) ( 1 ab2 + 1 )m+w 2 sin ( 1 2 (m+ w) ( π − 2 cot−1 (√ ab ))) dw Using equation (5) and substituting y by 1 2 log ( 1 ab2 + 1 ) + log(a) 2 + log(−b) + log(c) + iπ(2y + 1) and multiplying both sides by e2iπmy+iπm, simplifying we get R. Reynolds, A. Stauffer / Eur. J. Pure Appl. Math, 14 (3) (2021), 723-736 726 ie−imt+2iπmy+iπm 2k! (2iπ)k ( − i log ( 1 ab2 + 1 ) 4π − i log(a) 4π − i log(−b) 2π − i log(c) 2π − t 2π + 1 2 (2y + 1) )k − (2iπ)ke2imt ( − i log ( 1 ab2 + 1 ) 4π − i log(a) 4π − i log(−b) 2π − i log(c) 2π + t 2π + 1 2 (2y+ 1) )k = 1 2πi ∫ C w−k−1 sin(t(m+w)) exp ( w ( 1 2 log ( 1 ab2 + 1 ) + log(a) 2 + log(−b) + log(c) + iπ(2y + 1) ) + 2iπmy + iπm ) dw (6) Next we take the infinite sum over y ∈ [0,∞) and replace t by 1 2 ( π − 2 cot−1 ( √ ab) ) and multiply both sides by −2iπa m−1 2 (−b)m ( 1 ab2 + 1 )m/2 simplifying to get R. Reynolds, A. Stauffer / Eur. J. Pure Appl. Math, 14 (3) (2021), 723-736 727 (7) 2ke iπk 2 πk+1a m−1 2 (−b)m k! ( 1 ab2 + 1 )m/2( e 1 2 im(2 cot−1( √ ab)+π) Φ ( e2imπ,−k,− i ( 2i cot−1 ( √ ab) + log(a) + log ( 1 + 1 b2a ) + 2 log(−b) + 2 log(c) + iπ ) 4π ) − e 1 2 im(3π−2 cot−1( √ ab)) Φ ( e2imπ,−k,− i ( −2i cot−1 ( √ ab) + log(a) + log ( 1 + 1 b2a ) + 2 log(−b) + 2 log(c) + 3iπ ) 4π )) = 1 2πi ∞∑ y=0 ∫ C w−k−1 sin(t(m+ w)) exp ( w ( 1 2 log ( 1 ab2 + 1 ) + log(a) 2 + log(−b) + log(c) + iπ(2y + 1) ) + 2iπmy + iπm ) dw = 1 2πi ∫ C ∞∑ y=0 w−k−1 sin(t(m+ w)) exp ( w ( 1 2 log ( 1 ab2 + 1 ) + log(a) 2 + log(−b) + log(c) + iπ(2y + 1) ) + 2iπmy + iπm ) dw = 1 2πi ∫ C πcww−k−1a 1 2 (m+w−1)(−b)m+w csc(π(m+ w)) ( 1 ab2 + 1 )m+w 2 sin ( 1 2 (m+ w) ( π − 2 cot−1 (√ ab ))) dw from equation (1.232.3) in [3] where Im(m+w) > 0 in order for the sum to converge. 5.3. Derivation of the second contour integral In this section we derive the second contour integral given by (8) 1 2πi ∫ C πcww−k−1a 1 2 (m+w−1)bm+w csc(π(m+ w)) ( 1 ab2 + 1 )m+w 2 sin ( 1 2 (m+ w) ( 2 cot−1 (√ ab ) + π )) dw In this derivation we proceed as above but multiply by −2iπa m−1 2 bm ( 1 ab2 + 1 )m/2 and replace t by 1 2 ( 2 cot−1 ( √ ab) + π ) and simplifying to get R. Reynolds, A. Stauffer / Eur. J. Pure Appl. Math, 14 (3) (2021), 723-736 728 2ke iπk 2 πk+1a m−1 2 bm k! ( 1 ab2 + 1 )m/2( e 1 2 im(π−2 cot−1( √ ab)) Φ ( e2imπ,−k,− i ( −2i cot−1 ( √ ab) + log(a) + log ( 1 + 1 b2a ) + 2 log(b) + 2 log(c) + iπ ) 4π ) − e 1 2 im(2 cot−1( √ ab)+3π) Φ ( e2imπ,−k,− i ( 2i cot−1 ( √ ab) + log(a) + log ( 1 + 1 b2a ) + 2 log(b) + 2 log(c) + 3iπ ) 4π )) = 1 2πi ∫ C πcww−k−1a 1 2 (m+w−1)bm+w csc(π(m+ w)) ( 1 ab2 + 1 )m+w 2 sin ( 1 2 (m+ w) ( 2 cot−1 (√ ab ) + π )) dw (9) from equation (1.232.3) in [3] where Im(m+w) > 0 in order for the sum to converge. 6. The Stieltjes transform in terms of the Lerch function Since the right-hand side of equation (2) is equal to the sum of the right-hand sides of equations (8) and (9) we can equate the left-hand sides and simplifying the factorial to get (10) ∫ ∞ 0 (1− bx)m logk(c(1− bx)) + (bx+ 1)m logk(c(bx+ 1)) a2 + x2 dx = 2ke iπk 2 πk+1am−1(−b)m ( 1 a2b2 + 1 )m/2( e 1 2 im(2 cot−1(ab)+π) Φ ( e2imπ,−k,− i ( 2i cot−1(ab) + log ( a2 ) + log ( 1 + 1 a2b2 ) + 2 log(−b) + 2 log(c) + iπ ) 4π ) − e 1 2 im(3π−2 cot−1(ab)) Φ ( e2imπ,−k,− i ( −2i cot−1(ab) + log ( a2 ) + log ( 1 + 1 a2b2 ) + 2 log(−b) + 2 log(c) + 3iπ ) 4π )) + 2ke iπk 2 πk+1am−1bm ( 1 a2b2 + 1 )m/2( e 1 2 im(π−2 cot−1(ab)) Φ ( e2imπ,−k,− i ( −2i cot−1(ab) + log ( a2 ) + log ( 1 + 1 a2b2 ) + 2 log(b) + 2 log(c) + iπ ) 4π ) − e 1 2 im(2 cot−1(ab)+3π) Φ ( e2imπ,−k,− i ( 2i cot−1(ab) + log ( a2 ) + log ( 1 + 1 a2b2 ) + 2 log(b) + 2 log(c) + 3iπ ) 4π )) R. Reynolds, A. Stauffer / Eur. J. Pure Appl. Math, 14 (3) (2021), 723-736 729 7. Definite integrals in terms of the Hurwitz zeta function Using equation (10) replacing b by β, a by α and setting c = 1 followed by taking the sum over m ∈ [0,∞) and simplifying in terms of the Hurwitz zeta function we get∫ ∞ 0 logk(1− βx)− logk(βx+ 1) x (α2 + x2) dx = − i2 ke iπk 2 πk+1 α2 ( ζ ( −k, i(−2 log(i− αβ)− 3iπ) 4π ) − ζ ( −k,− i(2 log(αβ − i) + iπ) 4π )) (11) Using equation (10) and setting m = 0 and replacing a by √ a and simplifying in terms of the Hurwitz zeta function ζ(s, v) we get∫ ∞ 0 logk(c− bcx) + logk(bcx+ c) a+ x2 dx = (2i)kπk+1 √ a ( ζ ( −k, − i ( −2i cot−1 ( √ ab) + log(a) + log ( 1 + 1 b2a ) + 2 log(b) + 2 log(c) + iπ ) 4π ) − ζ ( −k, − i ( −2i cot−1 ( √ ab) + log(a) + log ( 1 + 1 b2a ) + 2 log(b) + 2 log(c) + 5iπ ) 4π )) (12) 8. Derivation of entry 4.535.7 in [3] Using (11) and setting k = α = 1 and replacing β by −ip and simplifying we get (13) ∫ ∞ 0 tan−1(px) x3 + x dx = 1 2 π log(p+ 1) 9. Derivation of entry 4.535.8 in [3] Using (11) and setting k = 1, β = −p, α = i and simplifying we get (14) ∫ ∞ 0 tan−1(px) x− x3 dx = 1 4 π(2 log(p+ i)− iπ) 10. Derivation of entry 4.535.9 in [3] Using (11) and setting k = 1 and replacing β by −iq and α by p and simplifying we get (15) ∫ ∞ 0 tan−1(qx) p2x+ x3 dx = π log(pq + 1) 2p2 R. Reynolds, A. Stauffer / Eur. J. Pure Appl. Math, 14 (3) (2021), 723-736 730 11. Derivation of entry 4.535.10 in [3] In this evaluation we will derive the definite integrals for both the Arctangent and Hyperbolic tangent functions. Using (11) and setting k = 1 and replacing β by q and α by 1/p simplifying we get (16) ∫ ∞ 0 tanh−1(qx) p2x3 + x dx = 1 8 ( − log ( −q p + i ) + log ( q p − i ) − iπ )( log ( −q p + i ) + log ( q p − i )) Next we multiply by −1/i, replace p by −ip and q by −iq simplifying to get (17) ∫ ∞ 0 tan−1(qx) x− p2x3 dx = 1 2 π log ( 1 + iq p ) The formula given in [3] is in error. 12. Derivation of entry 4.535.11 in [3] In this evaluation we will derive the definite integrals for both the Arctangent and Hyperbolic tangent functions. Using (10) and setting m = 0, k = 1 and replacing β by q and α by 1/p and simplifying we get∫ ∞ 0 tanh−1(bx) ax+ x3 dx = − (log(−b)− log(b)) ( log ( 1 ab2 + 1 ) + log(a) + log(−b) + log(b) ) + 2π cot−1 ( √ ab) 4a (18) Next we split the left-hand side to get∫ ∞ 0 ( tanh−1(bx) x − x tanh−1(bx) a+ x2 ) dx= 1 4 ( −(log(−b)− log(b)) ( log ( 1 ab2 +1 ) +log(a) + log(−b) + log(b) ) − 2π cot−1 (√ ab )) (19) Next we take the first partial derivative with respect to a simplifying to get (20) ∫ ∞ 0 x tanh−1(bx) (a2 + x2)2 dx = b ( π√ a2 − b log(−b) + b log(b) ) 4a2b2 + 4 Next replacing b by ib and simplifying we get (21) ∫ ∞ 0 x tan−1(bx) (a2 + x2)2 dx = πb 4a(ab+ 1) R. Reynolds, A. Stauffer / Eur. J. Pure Appl. Math, 14 (3) (2021), 723-736 731 13. Derivation of entry 4.295.1 in [3] Using (12) and setting k = c = 1 and simplifying we get∫ ∞ 0 log ( 1− b2x2 ) a+ x2 dx = 1 2π ( log ( 1 ab2 + 1 ) + log(a) + log(−b) + log(b) ) + (log(b)− log(−b)) cot−1 ( √ ab) √ a (22) Next we replace b by i √ µ√ β and a by γ simplifying to get (23) ∫ ∞ 0 log ( β + µx2 ) γ + x2 dx = π log (√ β + √ γ √ µ ) √ γ The equation quoted in [3] is not valid for general complex numbers, for example when Re(γ) < 0. 14. Derivation of entry 4.295.7 in [3] Using (23) and replacing β by a2, µ by b2 and γ by ( c g )2 and simplifying we get (24) ∫ ∞ 0 log ( a2 + b2x2 ) c2 + g2x2 dx = π log ( ag+bc g ) cg 15. Derivation of entry 4.295.8 in [3] Using (24) and replacing g by ig and simplifying we get (25) ∫ ∞ 0 log ( a2 + b2x2 ) c2 − g2x2 dx = − iπ log ( − i(bc+iag) g ) cg 16. Derivation of entry 4.295.9 in [3] We will form two equations by using (24) and setting β = 1 and replacing µ by p2 for the first equation and then replacing p by q for the second, subtracting and simplifying we get (26) ∫ ∞ 0 log ( p2x2 + 1 ) − log ( q2x2 + 1 ) γ + x2 dx = π log (√ γp+1√ γq+1 ) √ γ Next we apply L’Hopital’s rule as γ → 0 to the right-hand side simplifying to get (27) ∫ ∞ 0 log ( p2x2 + 1 ) − log ( q2x2 + 1 ) x2 dx = π(p− q) R. Reynolds, A. Stauffer / Eur. J. Pure Appl. Math, 14 (3) (2021), 723-736 732 17. Derivation of entry 4.295.22 in [3] Using (24) setting a = 1 and replacing c by r, g by q, b by p and simplifying we get (28) ∫ ∞ 0 log ( p2x2 + 1 ) q2x2 + r2 dx = π log ( pr+q q ) qr 18. Derivation of entry 4.295.25 in [3] Using (24) and taking the first partial derivative with respect to c and simplifying we get (29) ∫ ∞ 0 log ( a2 + b2x2 ) (c2 + g2x2)2 dx = π log ( ag+bc g ) 2c3g − πb 2c2g(ag + bc) 19. Derivation of entry 4.295.26 in [3] Using (24) and taking the first partial derivative with respect to g and simplifying we get (30) ∫ ∞ 0 x2 log ( a2 + b2x2 ) (c2 + g2x2)2 dx = πb 2g3(ag + bc) + π log ( ag+bc g ) 2cg3 20. Definite logarithmic integral in terms π Using (12) and setting c = 1, b = 1 and a = 1 simplifying we get (31) ∫ ∞ 0 logk(1− x) + logk(x+ 1) x2 + 1 dx = (2i)kπk+1 ( ζ ( −k,− −7π 2 + i log(2) 4π ) − ζ ( −k, 9π 2 − i log(2) 4π )) + (2i)kπk+1 ( ζ ( −k,− −π 2 + i log(2) 4π ) − ζ ( −k, 7π 2 − i log(2) 4π )) Next we apply L’Hopital’s rule as k → −1 and simplifying to get (32) ∫ ∞ 0 log ( 1− x2 ) (x2 + 1) log(1− x) log(x+ 1) dx = 4π log(4) + iπ R. Reynolds, A. Stauffer / Eur. J. Pure Appl. Math, 14 (3) (2021), 723-736 733 21. Definite nested logarithmic integral in terms π Using (12) and taking the first partial derivative with respect to k setting k = 0, c = 1, b = 1 and a = 1 and simplifying we get (33) ∫ ∞ 0 log(log(1− x)) + log(log(x+ 1)) x2 + 1 dx = 1 2 π ( 2logΓ ( π − 2i log(2) 8π ) − 2logΓ ( −7 8 − i log(2) 4π ) + 3iπ + log ( 4π2(π − 2i log(2))2 (7π + 2i log(2))2 )) Next simplifying the right-hand side we get (34) ∫ ∞ 0 log(log(1− x) log(x+ 1)) x2 + 1 dx = π log ( 1 4 i(π − 2i log(2)) ) 22. Definite integral of the hyperbolic tangent and logarithmic functions Using (11) and setting k = 2 and simplifying we get∫ ∞ 0 log ( 1− β2x2 ) tanh−1(βx) x3 + α2x dx = −4 log3(−αβ + i) + 6iπ log2(−αβ + i)− 4 log3(αβ − i) + 6iπ log2(αβ − i) + 4iπ3 48α2 (35) Next we apply L’Hopital’s rule to the right-hand side as α→ 0 and upon inspection of this closed form solution we are able to write down the conditional form given by ∫ ∞ 0 log ( 1− β2x2 ) tanh−1(βx) x3 dx =  1 2 iπβ 2 if Im(β) < 0, 1 2 iπβ|β| if Im(β) = 0, −1 2 iπβ|β| if Im(β) > 0. (36) We can also expand the left-hand side of equation (35) to get (37) ∫ ∞ 0 ( log ( 1− β2x2 ) tanh−1(βx) x − x log ( 1− β2x2 ) tanh−1(βx) α2 + x2 ) dx = 1 48 ( −4 log3(−αβ + i)− 6iπ log2(−αβ + i)− π2 log(−αβ + i) − (π + i log(αβ − i)) ( 2(π + 2i log(αβ − i)) log(αβ − i) + 3iπ2 )) and take the first partial derivative with respect to α, replacing β by −iβ simplifying to get (38) ∫ ∞ 0 x log ( β2x2 + 1 ) tan−1(βx) (α2 + x2)2 dx = πβ log ( (αβ + 1)2 ) 4α(αβ + 1) R. Reynolds, A. Stauffer / Eur. J. Pure Appl. Math, 14 (3) (2021), 723-736 734 23. Definite integral representation for π Using (10) and setting b = c = k = 1 and simplifying we get ∫ ∞ 0 (1− x)m log(1− x) + (x+ 1)m log(x+ 1) a+ x2 dx = πe iπm 2 ( √ a− i)m log ( − ( √ a− i)2 ) 2 √ a (39) Next we apply L’Hopital’s rule as a→ 0 to the right-hand side to get (40) ∫ ∞ 0 (1− x)m log(1− x) + (x+ 1)m log(x+ 1) x2 dx = iπ Next we take the definite integral over m ∈ [0,m] to get (41) ∫ ∞ 0 (1− x)m + (x+ 1)m − 2 x2 dx = iπm where −1 < Re(m) < 1. REFERENCES 735 24. Table of integrals f(x) ∫∞ 0 f(x)dx tan−1(px) x3+x 1 2π log(p+ 1) tan−1(px) x−x3 1 4π(2 log(p+ i)− iπ) tan−1(qx) p2x+x3 π log(pq+1) 2p2 tan−1(qx) x−p2x3 1 4π log ( p2+q2 p2 ) x tan−1(bx) (a2+x2)2 πb 4a(ab+1) log(β+µx2) γ+x2 π log( √ β+ √ γ √ µ)√ γ log(a2+b2x2) c2+g2x2 π log ( ag+bc g ) cg log(a2+b2x2) c2−g2x2 − iπ log ( − i(bc+iag) g ) cg log(p2x2+1)−log(q2x2+1) x2 π(p− q) log(p2x2+1) q2x2+r2 π log ( pr+q q ) qr log(a2+b2x2) (c2+g2x2)2 π log ( ag+bc g ) 2c3g − πb 2c2g(ag+bc) x2 log(a2+b2x2) (c2+g2x2)2 πb 2g3(ag+bc) + π log ( ag+bc g ) 2cg3 log(1−x2) (x2+1) log(1−x) log(x+1) 4π log(4)+iπ log(log(1−x) log(x+1)) x2+1 π log ( 1 4 i(π − 2i log(2)) ) (1−x)m log(1−x)+(x+1)m log(x+1) x2 iπ Table 1: Table of definite integrals Acknowledgements Supported by The Natural Sciences and Engineering Research Council of Canada (NSERC), Grant number 504070. References [1] D. Bierens de Haan. Nouvelles tables d’intégrales définies. P. Engels, Leiden, 1867. [2] A. Erdélyi. Tables of Integral Transforms. McGraw-Hill, New York, 1954. REFERENCES 736 [3] I. S. Gradshteyn and I. M. Ryzhik. Table of integrals, series, and products. Else- vier/Academic Press, Amsterdam, seventh edition, 2007. Translated from the Rus- sian, Translation edited and with a preface by Alan Jeffrey and Daniel Zwillinger, With one CD-ROM (Windows, Macintosh and UNIX). [4] A Reynolds, R.; Stauffer. A definite integral involving the logarithmic function in terms of the lerch function. Mathematics, 1148(7), 2019. [5] A Reynolds, R.; Stauffer. Definite integral of arctangent and polylogarithmic func- tions expressed as a series. Mathematics, 1099(7), 2019. [6] A Reynolds, R.; Stauffer. A definite integral involving the logarithmic function in terms of the lerch function. Mathematics, 687(7), 2020. [7] A Reynolds, R.; Stauffer. Definite integrals involving product of logarithmic functions and logarithm of square root functions expressed in terms of special functions. AIMS Mathematics, (5), 2020. [8] A Reynolds, R.; Stauffer. Integrals in gradshteyn and ryzhik: hyperbolic and alge- braic functions. International Mathematical Forum, 15(6):255–263, 2020. [9] A Reynolds, R.; Stauffer. A method for evaluating definite integrals in terms of special functions with examples. International Mathematical Forum, 15(5):235–244, 2020.