18.16 Zeros18.18 Sums

§18.17 Integrals

Contents

§18.17(i) Indefinite Integrals

§18.17(ii) Integral Representations for Products

Legendre

18.17.6 \mathop{P_{{n}}\/}\nolimits\!\left(\mathop{\cos\/}\nolimits\theta _{1}\right)\mathop{P_{{n}}\/}\nolimits\!\left(\mathop{\cos\/}\nolimits\theta _{2}\right)=\frac{1}{\pi}\int _{0}^{\pi}\mathop{P_{{n}}\/}\nolimits\!\left(\mathop{\cos\/}\nolimits\theta _{1}\mathop{\cos\/}\nolimits\theta _{2}+\mathop{\sin\/}\nolimits\theta _{1}\mathop{\sin\/}\nolimits\theta _{2}\mathop{\cos\/}\nolimits\phi\right)d\phi.

For formulas for Jacobi and Laguerre polynomials analogous to (18.17.5) and (18.17.6), see Koornwinder (1974, 1977).

§18.17(iii) Nicholson-Type Integrals

Hermite

18.17.8 \left(\mathop{H_{{n}}\/}\nolimits\!\left(x\right)\right)^{2}+2^{n}(n!)^{2}e^{{x^{2}}}\left(\mathop{V\/}\nolimits\!\left(-n-\tfrac{1}{2},2^{{\frac{1}{2}}}x\right)\right)^{2}=\frac{2^{{n+\frac{3}{2}}}n!\, e^{{x^{2}}}}{\pi}\int _{0}^{\infty}\frac{e^{{-(2n+1)t+x^{2}\mathop{\tanh\/}\nolimits t}}}{(\mathop{\sinh\/}\nolimits 2t)^{{\frac{1}{2}}}}dt.

For the parabolic cylinder function \mathop{V\/}\nolimits\!\left(a,z\right) see §12.2. For similar formulas for ultraspherical polynomials see Durand (1975), and for Jacobi and Laguerre polynomials see Durand (1978).

§18.17(iv) Fractional Integrals

§18.17(v) Fourier Transforms

Throughout this subsection we assume y>0; sometimes however, this restriction can be eased by analytic continuation.

Jacobi

18.17.16 \int _{{-1}}^{1}(1-x)^{{\alpha}}(1+x)^{{\beta}}\mathop{P^{{(\alpha,\beta)}}_{{n}}\/}\nolimits\!\left(x\right)e^{{ixy}}dx=\frac{(iy)^{n}e^{{iy}}}{n!}2^{{n+\alpha+\beta+1}}\mathop{\mathrm{B}\/}\nolimits\!\left(n+\alpha+1,n+\beta+1\right)\mathop{{{}_{{1}}F_{{1}}}\/}\nolimits\!\left(n+\alpha+1;2n+\alpha+\beta+2;-2iy\right).

For the beta function \mathop{\mathrm{B}\/}\nolimits\!\left(a,b\right) see §5.12, and for the confluent hypergeometric function \mathop{{{}_{{1}}F_{{1}}}\/}\nolimits see (16.2.1) and Chapter 13.

Hermite

18.17.22 \frac{1}{2\sqrt{\pi}}\int _{{-\infty}}^{{\infty}}e^{{-\frac{1}{4}x^{2}}}\mathop{\mathit{He}_{{n}}\/}\nolimits\!\left(x\right)e^{{\frac{1}{2}ixy}}dx=i^{n}e^{{-\frac{1}{4}y^{2}}}\mathop{\mathit{He}_{{n}}\/}\nolimits\!\left(y\right),
18.17.23 \int _{0}^{{\infty}}e^{{-\frac{1}{2}x^{2}}}\mathop{\mathit{He}_{{2n}}\/}\nolimits\!\left(x\right)\mathop{\cos\/}\nolimits\!\left(xy\right)dx=(-1)^{n}\sqrt{\tfrac{1}{2}\pi}y^{{2n}}e^{{-\frac{1}{2}y^{2}}},
18.17.24 \int _{0}^{{\infty}}e^{{-x^{2}}}\mathop{\mathit{He}_{{2n}}\/}\nolimits\!\left(2x\right)\mathop{\cos\/}\nolimits\!\left(xy\right)dx=(-1)^{n}\tfrac{1}{2}\sqrt{\pi}e^{{-\frac{1}{4}y^{2}}}\mathop{\mathit{He}_{{2n}}\/}\nolimits\!\left(y\right).
18.17.25 \int _{0}^{\infty}e^{{-\frac{1}{2}x^{2}}}\mathop{\mathit{He}_{{n}}\/}\nolimits\!\left(x\right)\mathop{\mathit{He}_{{n+2m}}\/}\nolimits\!\left(x\right)\mathop{\cos\/}\nolimits\!\left(xy\right)dx=(-1)^{m}\sqrt{\tfrac{1}{2}\pi}n!\, y^{{2m}}e^{{-\frac{1}{2}y^{2}}}\mathop{L^{{(2m)}}_{{n}}\/}\nolimits\!\left(y^{2}\right),
18.17.26 \int _{0}^{\infty}e^{{-\frac{1}{2}x^{2}}}\mathop{\mathit{He}_{{n}}\/}\nolimits\!\left(x\right)\mathop{\mathit{He}_{{n+2m+1}}\/}\nolimits\!\left(x\right)\mathop{\sin\/}\nolimits\!\left(xy\right)dx=(-1)^{m}\sqrt{\tfrac{1}{2}\pi}n!\, y^{{2m+1}}e^{{-\frac{1}{2}y^{2}}}\mathop{L^{{(2m+1)}}_{{n}}\/}\nolimits\!\left(y^{2}\right).
18.17.27 \int _{0}^{\infty}e^{{-\frac{1}{2}x^{2}}}\mathop{\mathit{He}_{{2n+1}}\/}\nolimits\!\left(x\right)\mathop{\sin\/}\nolimits\!\left(xy\right)dx=(-1)^{n}\sqrt{\tfrac{1}{2}\pi}y^{{2n+1}}e^{{-\frac{1}{2}y^{2}}},
18.17.28 \int _{0}^{\infty}e^{{-x^{2}}}\mathop{\mathit{He}_{{2n+1}}\/}\nolimits\!\left(2x\right)\mathop{\sin\/}\nolimits\!\left(xy\right)dx=(-1)^{n}\tfrac{1}{2}\sqrt{\pi}e^{{-\frac{1}{4}y^{2}}}\mathop{\mathit{He}_{{2n+1}}\/}\nolimits\!\left(y\right).

§18.17(vi) Laplace Transforms

§18.17(vii) Mellin Transforms

§18.17(viii) Other Integrals

§18.17(ix) Compendia

For further integrals, see Apelblat (1983, pp. 189–204), Erdélyi et al. (1954a, pp. 38–39, 94–95, 170–176, 259–261, 324), Erdélyi et al. (1954b, pp. 42–44, 271–294), Gradshteyn and Ryzhik (2000, pp. 788–806), Gröbner and Hofreiter (1950, pp. 23–30), Marichev (1983, pp. 216–247), Oberhettinger (1972, pp. 64–67), Oberhettinger (1974, pp. 83–92), Oberhettinger (1990, pp. 44–47 and 152–154), Oberhettinger and Badii (1973, pp. 103–112), Prudnikov et al. (1986b, pp. 420–617), Prudnikov et al. (1992a, pp. 419–476), and Prudnikov et al. (1992b, pp. 280–308).