23,312 research outputs found
Sharp bounds for harmonic numbers
In the paper, we first survey some results on inequalities for bounding
harmonic numbers or Euler-Mascheroni constant, and then we establish a new
sharp double inequality for bounding harmonic numbers as follows: For
, the double inequality
-\frac{1}{12n^2+{2(7-12\gamma)}/{(2\gamma-1)}}\le H(n)-\ln
n-\frac1{2n}-\gamma<-\frac{1}{12n^2+6/5} is valid, with equality in the
left-hand side only when , where the scalars
and are the best possible.Comment: 7 page
Some sharp inequalities involving Seiffert and other means and their concise proofs
In the paper, by establishing the monotonicity of some functions involving
the sine and cosine functions, the authors provide concise proofs of some known
inequalities and find some new sharp inequalities involving the Seiffert,
contra-harmonic, centroidal, arithmetic, geometric, harmonic, and root-square
means of two positive real numbers and with .Comment: 10 page
The monotonicity and convexity of a function involving digamma one and their applications
Let be defined on or by the formula% \begin{equation*}
\mathcal{L}(x,a)=\tfrac{1}{90a^{2}+2}\ln \left( x^{2}+x+\tfrac{3a+1}{3}%
\right) +\tfrac{45a^{2}}{90a^{2}+2}\ln \left( x^{2}+x+\allowbreak \tfrac{%
15a-1}{45a}\right) . \end{equation*} We investigate the monotonicity and
convexity of the function , where denotes the Psi function. And, we
determine the best parameter such that the inequality \psi \left(
x+1\right) \right) \mathcal{L}% (x,a) holds for or , and then, some new and very
high accurate sharp bounds for pis function and harmonic numbers are presented.
As applications, we construct a sequence
defined by , which
gives extremely accurate values for .Comment: 20 page
Some remarks on harmonic projection operators on spheres
We give a survey of recent works concerning the mapping properties of joint harmonic projection operators, mapping the space of square integrable functions on complex and quaternionic spheres onto the eigenspaces of the Laplace-Beltrami operator and of a suitably defined subLaplacian. In particular, we discuss similarities and differences between the real, the complex and the quaternionic framework
- …