The integrals below involve `tanh ax`.
1) `int tanh ax dx = 1/a ln cosh ax`
2) `int tanh^2 ax dx = x-(tanh ax)/a`
3) `int tanh^3 ax dx = 1/a ln cosh ax-(tanh^2 ax)/(2a)`
4) `int tanh^n ax\ text{sech}\^2 ax dx = (tanh^(n+1)ax)/((n+1)a)`
5) `int (\text{sech}\^2 ax)/(tanh ax) dx = 1/a ln tanh ax`
6) `int 1/(tanh ax) dx = 1/a ln sinh ax`
7) `int x tanh ax dx = 1/a^2{(ax)^3/3-(ax)^5/15+(2(ax)^7)/105-...((-1)^(n-1)2^(2n)(2^(2n)-1)B_n(ax)^(2n+1))/((2n+1)!)+...}`
8) `int x*tanh^2 ax dx = x^2/2-(x tanh ax)/a+1/a^2 ln cosh ax`
9) `int (tanh ax)/x dx = ax-(ax)^3/9+(2(ax)^5)/75-...((-1)^(n-1)2^(2n)(2^(2n)-1)B_n(ax)^(2n-1))/((2n-1)(2n)!)+...`
10) `int 1/(p+q tanh ax) dx = (px)/(p^2-q^2)-q/(a(p^2-q^2)) ln (q sinh ax+p cosh ax)`
11) `int tanh^n ax dx = (-tanh^(n-1) ax)/(a(n-1))+ int tanh^(n-2) ax dx`