Let $k\in\mathbb{N}$, $\alpha\in\mathbb{R}$, and $a,b\in\mathbb{R}$ such that $a,b>0$. Then \begin{equation}\label{alpha-n=1-k-odd}\tag{q1} \int_0^\infty\frac{\sin^{2k-1}t}{t}\sin(\alpha t)\operatorname{d} t =\frac{(-1)^{k-1}}{2^{2k}}\sum_{q=0}^{2k-1}(-1)^q\binom{2k-1}{q}\ln\biggl|\frac{2q-2k+1-\alpha}{2q-2k+1+\alpha}\biggr| \end{equation} and \begin{equation}\label{a-b-n=1-k-odd}\tag{q2} \int_0^\infty\frac{\sin^{2k}(a x)}{x}\cos(bx)\operatorname{d} x =\frac{(-1)^{k-1}}{2^{2k+1}}\sum_{q=0}^{2k-1}(-1)^q\binom{2k-1}{q}\ln\biggl|\frac{4a^2(q-k)^2-b^2}{4a^2(q-k+1)^2-b^2}\biggr|. \end{equation} Recently, I derived the formulas \eqref{alpha-n=1-k-odd} and \eqref{a-b-n=1-k-odd}. The motivation comes from related results on pp. 464--471 in the monogrpah [1] below and those results in the papers [2] to [6].
Let $m,n\in\mathbb{N}$ such that $n\ge2$ and $m-n\ge1$ is odd and let $a,b,\alpha\in\mathbb{R}$ such that $a>0$ and $b\ge0$. How to compute or where to find the improper integrals \begin{equation*} \int_0^\infty\frac{\sin^{m-1}t}{t^{n}}\sin(\alpha t)\operatorname{d} t \quad\text{and}\quad \int_0^\infty\frac{\sin^{m}(a x)}{x^{n}}\cos(bx)\operatorname{d} x? \end{equation*} Due to related results in the monographs [7] and [8], I think that this problem is interesting and significant.
References
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