1. Trang chủ
  2. » Ngoại Ngữ

HANDBOOK OFINTEGRAL EQUATIONS phần 5 ppsx

86 277 0

Đang tải... (xem toàn văn)

Tài liệu hạn chế xem trước, để xem đầy đủ mời bạn chọn Tải xuống

THÔNG TIN TÀI LIỆU

Thông tin cơ bản

Định dạng
Số trang 86
Dung lượng 7,79 MB

Nội dung

2 ◦ .Forλ(2A + λ)=–k 2 < 0, the general solution of equation (1) is given by y(x)=C 1 cosh(kx)+C 2 sinh(kx)+f(x) – 2Aλ k  x a sinh[k(x – t)] f(t) dt, (3) where C 1 and C 2 are arbitrary constants. For λ(2A + λ)=k 2 > 0, the general solution of equation (1) is given by y(x)=C 1 cos(kx)+C 2 sin(kx)+f(x) – 2Aλ k  x a sin[k(x – t)] f(t) dt. (4) For λ =2A, the general solution of equation (1) is given by y(x)=C 1 + C 2 x + f(x)+4A 2  x a (x – t)f(t) dt. (5) The constants C 1 and C 2 in solutions (3)–(5) are determined by conditions (2). 30. y(x)+A  b a t sin(λ|x – t|)y(t) dt = f(x). This is a special case of equation 4.9.39 with g(t)=At. The solution of the integral equation can be written via the Bessel functions (or modified Bessel functions) of order 1/3. 31. y(x)+A  b a sin 3 (λ|x – t|)y(t) dt = f(x). Using the formula sin 3 β = – 1 4 sin 3β + 3 4 sin β, we arrive at an equation of the form 4.5.32 with n =2: y(x)+  b a  – 1 4 A sin(3λ|x – t|)+ 3 4 A sin(λ|x – t|)  y(t) dt = f(x). 32. y(x)+  b a  n  k=1 A k sin(λ k |x – t|)  y(t) dt = f (x), –∞ < a < b < ∞. 1 ◦ . Let us remove the modulus in the kth summand of the integrand: I k (x)=  b a sin(λ k |x – t|)y(t) dt =  x a sin[λ k (x – t)]y(t) dt +  b x sin[λ k (t – x)]y(t) dt. (1) Differentiating (1) with respect to x twice yields I  k = λ k  x a cos[λ k (x – t)]y(t) dt – λ k  b x cos[λ k (t – x)]y(t) dt, I  k =2λ k y(x) – λ 2 k  x a sin[λ k (x – t)]y(t) dt – λ 2 k  b x sin[λ k (t – x)]y(t) dt, (2) where the primes denote the derivatives with respect to x. By comparing formulas (1) and (2), we find the relation between I  k and I k : I  k =2λ k y(x) – λ 2 k I k , I k = I k (x). (3) Page 286 © 1998 by CRC Press LLC © 1998 by CRC Press LLC 2 ◦ . With the aid of (1), the integral equation can be rewritten in the form y(x)+ n  k=1 A k I k = f(x). (4) Differentiating (4) with respect to x twice and taking into account (3), we find that y  xx (x)+σ n y(x) – n  k=1 A k λ 2 k I k = f  xx (x), σ n =2 n  k=1 A k λ k . (5) Eliminating the integral I n from (4) and (5) yields y  xx (x)+(σ n + λ 2 n )y(x)+ n–1  k=1 A k (λ 2 n – λ 2 k )I k = f  xx (x)+λ 2 n f(x). (6) Differentiating (6) with respect to x twice and eliminating I n–1 from the resulting equation with the aid of (6), we obtain a similar equation whose left-hand side is a second-order linear differential operator (acting on y) with constant coefficients plus the sum n–2  k=1 B k I k .Ifwe successively eliminate I n–2 , I n–3 , , with the aid of double differentiation, then we finally arrive at a linear nonhomogeneous ordinary differential equation of order 2n with constant coefficients. 3 ◦ . The boundary conditions for y(x) can be found by setting x = a in the integral equation and all its derivatives. (Alternatively, these conditions can be found by setting x = a and x = b in the integral equation and all its derivatives obtained by means of double differentiation.) 33. y(x) – λ  ∞ –∞ sin(x – t) x – t y(t) dt = f (x). Solution: y(x)=f(x)+ λ √ 2π – πλ  ∞ –∞ sin(x – t) x – t f(t) dt, λ ≠  2 π . • Reference: F. D. Gakhov and Yu. I. Cherskii (1978). 4.5-3. Kernels Containing Tangent 34. y(x) – λ  b a tan(βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = tan(βx) and h(t)=1. 35. y(x) – λ  b a tan(βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = 1 and h(t) = tan(βt). 36. y(x) – λ  b a [A tan(βx)+B tan(βt)]y(t) dt = f (x). This is a special case of equation 4.9.4 with g(x) = tan(βx). Page 287 © 1998 by CRC Press LLC © 1998 by CRC Press LLC 37. y(x) – λ  b a tan(βx) tan(βt) y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = tan(βx) and h(t)= 1 tan(βt) . 38. y(x) – λ  b a tan(βt) tan(βx) y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)= 1 tan(βx) and h(t) = tan(βt). 39. y(x) – λ  b a tan k (βx) tan m (µt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = tan k (βx) and h(t) = tan m (µt). 40. y(x) – λ  b a t k tan m (βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = tan m (βx) and h(t)=t k . 41. y(x) – λ  b a x k tan m (βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)=x k and h(t) = tan m (βt). 42. y(x) – λ  b a [A + B(x – t) tan(βt)]y(t) dt = f (x). This is a special case of equation 4.9.8 with h(t) = tan(βt). 43. y(x) – λ  b a [A + B(x – t) tan(βx)]y(t) dt = f (x). This is a special case of equation 4.9.10 with h(x) = tan(βx). 4.5-4. Kernels Containing Cotangent 44. y(x) – λ  b a cot(βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = cot(βx) and h(t)=1. 45. y(x) – λ  b a cot(βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = 1 and h(t) = cot(βt). 46. y(x) – λ  b a [A cot(βx)+B cot(βt)]y(t) dt = f (x). This is a special case of equation 4.9.4 with g(x) = cot(βx). Page 288 © 1998 by CRC Press LLC © 1998 by CRC Press LLC 47. y(x) – λ  b a cot(βx) cot(βt) y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = cot(βx) and h(t)= 1 cot(βt) . 48. y(x) – λ  b a cot(βt) cot(βx) y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)= 1 cot(βx) and h(t) = cot(βt). 49. y(x) – λ  b a cot k (βx) cot m (µt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = cot k (βx) and h(t) = cot m (µt). 50. y(x) – λ  b a t k cot m (βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = cot m (βx) and h(t)=t k . 51. y(x) – λ  b a x k cot m (βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)=x k and h(t) = cot m (βt). 52. y(x) – λ  b a [A + B(x – t) cot(βt)]y(t) dt = f (x). This is a special case of equation 4.9.8 with h(t) = cot(βt). 53. y(x) – λ  b a [A + B(x – t) cot(βx)]y(t) dt = f (x). This is a special case of equation 4.9.10 with h(x) = cot(βx). 4.5-5. Kernels Containing Combinations of Trigonometric Functions 54. y(x) – λ  b a cos k (βx) sin m (µt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = cos k (βx) and h(t) = sin m (µt). 55. y(x) – λ  b a [A sin(αx) cos(βt)+B sin(γx) cos(δt)]y(t) dt = f (x). This is a special case of equation 4.9.18 with g 1 (x) = sin(αx), h 1 (t)=A cos(βt), g 2 (x) = sin(γx), and h 2 (t)=B cos(δt). 56. y(x) – λ  b a tan k (γx) cot m (µt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = tan k (γx) and h(t) = cot m (µt). 57. y(x) – λ  b a [A tan(αx) cot(βt)+B tan(γx) cot(δt)]y(t) dt = f (x). This is a special case of equation 4.9.18 with g 1 (x) = tan(αx), h 1 (t)=A cot(βt), g 2 (x) = tan(γx), and h 2 (t)=B cot(δt). Page 289 © 1998 by CRC Press LLC © 1998 by CRC Press LLC 4.5-6. A Singular Equation 58. Ay(x) – B 2π  2π 0 cot  t – x 2  y(t) dt = f (x), 0 ≤ x ≤ 2π. Here the integral is understood in the sense of the Cauchy principal value. Without loss of generality we may assume that A 2 + B 2 =1. Solution: y(x)=Af(x)+ B 2π  2π 0 cot  t – x 2  f(t) dt + B 2 2πA  2π 0 f(t) dt. • Reference: I. K. Lifanov (1996). 4.6. Equations Whose Kernels Contain Inverse Trigonometric Functions 4.6-1. Kernels Containing Arccosine 1. y(x) – λ  b a arccos(βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arccos(βx) and h(t)=1. 2. y(x) – λ  b a arccos(βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = 1 and h(t) = arccos(βt). 3. y(x) – λ  b a arccos(βx) arccos(βt) y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arccos(βx) and h(t)= 1 arccos(βt) . 4. y(x) – λ  b a arccos(βt) arccos(βx) y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)= 1 arccos(βx) and h(t) = arccos(βt). 5. y(x) – λ  b a arccos k (βx) arccos m (µt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arccos k (βx) and h(t) = arccos m (µt). 6. y(x) – λ  b a t k arccos m (βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arccos m (βx) and h(t)=t k . 7. y(x) – λ  b a x k arccos m (βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)=x k and h(t) = arccos m (βt). Page 290 © 1998 by CRC Press LLC © 1998 by CRC Press LLC 8. y(x) – λ  b a [A + B(x – t) arccos(βx)]y(t) dt = f(x). This is a special case of equation 4.9.10 with h(x) = arccos(βx). 9. y(x) – λ  b a [A + B(x – t) arccos(βt)]y(t) dt = f(x). This is a special case of equation 4.9.8 with h(t) = arccos(βt). 4.6-2. Kernels Containing Arcsine 10. y(x) – λ  b a arcsin(βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arcsin(βx) and h(t)=1. 11. y(x) – λ  b a arcsin(βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = 1 and h(t) = arcsin(βt). 12. y(x) – λ  b a arcsin(βx) arcsin(βt) y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arcsin(βx) and h(t)= 1 arcsin(βt) . 13. y(x) – λ  b a arcsin(βt) arcsin(βx) y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)= 1 arcsin(βx) and h(t) = arcsin (βt). 14. y(x) – λ  b a arcsin k (βx) arcsin m (µt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arcsin k (βx) and h(t) = arcsin m (µt). 15. y(x) – λ  b a t k arcsin m (βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arcsin m (βx) and h(t)=t k . 16. y(x) – λ  b a x k arcsin m (βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)=x k and h(t) = arcsin m (βt). 17. y(x) – λ  b a [A + B(x – t) arcsin(βt)]y(t) dt = f(x). This is a special case of equation 4.9.8 with h(t) = arcsin(βt). 18. y(x) – λ  b a [A + B(x – t) arcsin(βx)]y(t) dt = f(x). This is a special case of equation 4.9.10 with h(x) = arcsin(βx). Page 291 © 1998 by CRC Press LLC © 1998 by CRC Press LLC 4.6-3. Kernels Containing Arctangent 19. y(x) – λ  b a arctan(βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arctan(βx) and h(t)=1. 20. y(x) – λ  b a arctan(βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = 1 and h(t) = arctan(βt). 21. y(x) – λ  b a [A arctan(βx)+B arctan(βt)]y(t) dt = f (x). This is a special case of equation 4.9.4 with g(x) = arctan(βx). 22. y(x) – λ  b a arctan(βx) arctan(βt) y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arctan(βx) and h(t)= 1 arctan(βt) . 23. y(x) – λ  b a arctan(βt) arctan(βx) y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)= 1 arctan(βx) and h(t) = arctan(βt). 24. y(x) – λ  b a arctan k (βx) arctan m (µt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arctan k (βx) and h(t) = arctan m (µt). 25. y(x) – λ  b a t k arctan m (βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arctan m (βx) and h(t)=t k . 26. y(x) – λ  b a x k arctan m (βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)=x k and h(t) = arctan m (βt). 27. y(x) – λ  b a [A + B(x – t) arctan(βt)]y(t) dt = f(x). This is a special case of equation 4.9.8 with h(t) = arctan(βt). 28. y(x) – λ  b a [A + B(x – t) arctan(βx)]y(t) dt = f(x). This is a special case of equation 4.9.10 with h(x) = arctan(βx). Page 292 © 1998 by CRC Press LLC © 1998 by CRC Press LLC 4.6-4. Kernels Containing Arccotangent 29. y(x) – λ  b a arccot(βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arccot(βx) and h(t)=1. 30. y(x) – λ  b a arccot(βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = 1 and h(t) = arccot(βt). 31. y(x) – λ  b a [A arccot(βx)+B arccot(βt)]y(t) dt = f (x). This is a special case of equation 4.9.4 with g(x) = arccot(βx). 32. y(x) – λ  b a arccot(βx) arccot(βt) y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arccot(βx) and h(t)= 1 arccot(βt) . 33. y(x) – λ  b a arccot(βt) arccot(βx) y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)= 1 arccot(βx) and h(t) = arccot(βt). 34. y(x) – λ  b a arccot k (βx) arccot m (µt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arccot k (βx) and h(t) = arccot m (µt). 35. y(x) – λ  b a t k arccot m (βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = arccot m (βx) and h(t)=t k . 36. y(x) – λ  b a x k arccot m (βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)=x k and h(t) = arccot m (βt). 37. y(x) – λ  b a [A + B(x – t) arccot(βt)]y(t) dt = f(x). This is a special case of equation 4.9.8 with h(t) = arccot(βt). 38. y(x) – λ  b a [A + B(x – t) arccot(βx)]y(t) dt = f(x). This is a special case of equation 4.9.10 with h(x) = arccot(βx). Page 293 © 1998 by CRC Press LLC © 1998 by CRC Press LLC 4.7. Equations Whose Kernels Contain Combinations of Elementary Functions 4.7-1. Kernels Containing Exponential and Hyperbolic Functions 1. y(x) – λ  b a e µ(x–t) cosh[β(x – t)]y(t) dt = f (x). This is a special case of equation 4.9.18 with g 1 (x)=e µx cosh(βx), h 1 (t)=e –µt cosh(βt), g 2 (x)=e µx sinh(βx), and h 2 (t)=–e –µt sinh(βt). 2. y(x) – λ  b a e µ(x–t) sinh[β(x – t)]y(t) dt = f (x). This is a special case of equation 4.9.18 with g 1 (x)=e µx sinh(βx), h 1 (t)=e –µt cosh(βt), g 2 (x)=e µx cosh(βx), and h 2 (t)=–e –µt sinh(βt). 3. y(x) – λ  b a te µ(x–t) sinh[β(x – t)]y(t) dt = f (x). This is a special case of equation 4.9.18 with g 1 (x)=e µx sinh(βx), h 1 (t)=te –µt cosh(βt), g 2 (x)=e µx cosh(βx), and h 2 (t)=–te –µt sinh(βt). 4.7-2. Kernels Containing Exponential and Logarithmic Functions 4. y(x) – λ  b a e µt ln(βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = ln(βx) and h(t)=e µt . 5. y(x) – λ  b a e µx ln(βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)=e µx and h(t) = ln(βt). 6. y(x) – λ  b a e µ(x–t) ln(βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)=e µx ln(βx) and h(t)=e –µt . 7. y(x) – λ  b a e µ(x–t) ln(βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)=e µx and h(t)=e –µt ln(βt). 8. y(x) – λ  b a e µ(x–t) (ln x – ln t)y(t) dt = f (x). This is a special case of equation 4.9.18 with g 1 (x)=e µx ln x, h 1 (t)=e –µt , g 2 (x)=e µx , and h 2 (t)=–e –µt ln t. Page 294 © 1998 by CRC Press LLC © 1998 by CRC Press LLC 9. y(x)+ b 2 – a 2 2a  ∞ 0 1 t exp  –a    ln x t     y(t) dt = f (x). Solution with a >0,b > 0, and x >0: y(x)=f(x)+ a 2 – b 2 2b  ∞ 0 1 t exp  –b    ln x t     f(t) dt. • Reference: F. D. Gakhov and Yu. I. Cherskii (1978). 4.7-3. Kernels Containing Exponential and Trigonometric Functions 10. y(x) – λ  b a e µt cos(βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = cos(βx) and h(t)=e µt . 11. y(x) – λ  b a e µx cos(βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)=e µx and h(t) = cos(βt). 12. y(x) – λ  ∞ 0 e µ(x–t) cos(xt)y(t) dt = f (x). Solution: y(x)= f(x) 1 – π 2 λ 2 + λ 1 – π 2 λ 2  ∞ 0 e µ(x–t) cos(xt)f(t) dt, λ ≠ ±  2/π. 13. y(x) – λ  b a e µ(x–t) cos[β(x – t)]y(t) dt = f (x). This is a special case of equation 4.9.18 with g 1 (x)=e µx cos(βx), h 1 (t)=e –µt cos(βt), g 2 (x)=e µx sin(βx), and h 2 (t)=e –µt sin(βt). 14. y(x) – λ  b a e µt sin(βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = sin(βx) and h(t)=e µt . 15. y(x) – λ  b a e µx sin(βt)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x)=e µx and h(t) = sin(βt). 16. y(x) – λ  ∞ 0 e µ(x–t) sin(xt)y(t) dt = f (x). Solution: y(x)= f(x) 1 – π 2 λ 2 + λ 1 – π 2 λ 2  ∞ 0 e µ(x–t) sin(xt)f(t) dt, λ ≠ ±  2/π. Page 295 © 1998 by CRC Press LLC © 1998 by CRC Press LLC [...]... b 50 tank (βx) lnm (µt)y(t) dt = f (x) y(x) – λ a This is a special case of equation 4.9.1 with g(x) = tank (βx) and h(t) = lnm (µt) b 51 tank (βt) lnm (µx)y(t) dt = f (x) y(x) – λ a This is a special case of equation 4.9.1 with g(x) = lnm (µx) and h(t) = tank (βt) b 52 cotk (βx) lnm (µt)y(t) dt = f (x) y(x) – λ a This is a special case of equation 4.9.1 with g(x) = cotk (βx) and h(t) = lnm (µt) b 53 ... (x) y(x) – λ a This is a special case of equation 4.9.1 with g(x) = lnm (µx) and h(t) = cothk (βt) 4.7 -5 Kernels Containing Hyperbolic and Trigonometric Functions b 34 coshk (βx) cosm (µt)y(t) dt = f (x) y(x) – λ a This is a special case of equation 4.9.1 with g(x) = coshk (βx) and h(t) = cosm (µt) b 35 coshk (βt) cosm (µx)y(t) dt = f (x) y(x) – λ a This is a special case of equation 4.9.1 with g(x) =... Y (z) + λ τ Jν (zτ )Y (τ ) dτ = F (z) 0 b 5 y(x) – λ [A + B(x – t)Jν (βt)]y(t) dt = f (x) a This is a special case of equation 4.9.8 with h(t) = Jν (βt) b 6 y(x) – λ [A + B(x – t)Jν (βx)]y(t) dt = f (x) a This is a special case of equation 4.9.10 with h(x) = Jν (βx) b 7 y(x) – λ [AJµ (αx) + BJν (βt)]y(t) dt = f (x) a This is a special case of equation 4.9 .5 with g(x) = AJµ (αx) and h(t) = BJν (βt)... h(x) = Yν (βx) b 13 y(x) – λ [AYµ (αx) + BYν (βt)]y(t) dt = f (x) a This is a special case of equation 4.9 .5 with g(x) = AYµ (αx) and h(t) = BYν (βt) b 14 y(x) – λ [AYµ (x)Yµ (t) + BYν (x)Yν (t)]y(t) dt = f (x) a This is a special case of equation 4.9.14 with g(x) = Yµ (x) and h(t) = Yν (t) b 15 y(x) – λ [AYµ (x)Yν (t) + BYν (x)Yµ (t)]y(t) dt = f (x) a This is a special case of equation 4.9.17 with... = Kν (βt) b 25 y(x) – λ [A + B(x – t)Kν (βt)]y(t) dt = f (x) a This is a special case of equation 4.9.8 with h(t) = Kν (βt) b 26 y(x) – λ [A + B(x – t)Kν (βx)]y(t) dt = f (x) a This is a special case of equation 4.9.10 with h(x) = Kν (βx) © 1998 by CRC Press LLC © 1998 by CRC Press LLC Page 301 b 27 y(x) – λ [AKµ (αx) + BKν (βt)]y(t) dt = f (x) a This is a special case of equation 4.9 .5 with g(x) =... Kµ (x) and h(t) = Kν (t) b 29 y(x) – λ [AKµ (x)Kν (t) + BKν (x)Kµ (t)]y(t) dt = f (x) a This is a special case of equation 4.9.17 with g(x) = Kµ (x) and h(t) = Kν (t) 4.9 Equations Whose Kernels Contain Arbitrary Functions 4.9-1 Equations With Degenerate Kernel: K(x, t) = g1 (x)h1 (t) + · · · + gn (x)hn (t) b 1 y(x) – λ g(x)h(t)y(t) dt = f (x) a 1◦ Assume that λ ≠ Solution: –1 b a g(t)h(t) dt –1... the equation has a unique solution, which is given by ∞ y(x) = f (x) + R(x – t)f (t) dt, –∞ 1 R(x) = √ 2π ∞ R(u)eiux du, R(u) = –∞ K(u) √ 1 – 2π K(u) • Reference: V A Ditkin and A P Prudnikov (19 65) ∞ 25 y(x) – K(x – t)y(t) dt = f (x) 0 The Wiener–Hopf equation of the second kind.* Here 0 ≤ x < ∞, K(x) ∈ L1 (–∞, ∞), f (x) ∈ L1 (0, ∞), and y(x) ∈ L1 (0, ∞) For the integral equation to be solvable,... LLC Page 319 4.9-3 Other Equations of the Form y(x) + b a K(x, t)y(t) dt = F (x) ∞ 26 y(x) – K(x + t)y(t) dt = f (x) –∞ The Fourier transform is used to solving this equation Solution: √ ∞ 1 f (u) + 2π f (–u)K(u) iux y(x) = √ e du, √ 2π –∞ 1 – 2π K(u)K(–u) where 1 f (u) = √ 2π ∞ ∞ 1 K(u) = √ 2π f (x)e–iux dx, –∞ K(x)e–iux dx –∞ • Reference: V A Ditkin and A P Prudnikov (19 65) ∞ 27 y(x) + eβt K(x +... case of equation 4.9.1 with g(x) = cotk (βx) and h(t) = lnm (µt) b 53 cotk (βt) lnm (µx)y(t) dt = f (x) y(x) – λ a This is a special case of equation 4.9.1 with g(x) = lnm (µx) and h(t) = cotk (βt) 4.8 Equations Whose Kernels Contain Special Functions 4.8-1 Kernels Containing Bessel Functions b 1 y(x) – λ Jν (βx)y(t) dt = f (x) a This is a special case of equation 4.9.1 with g(x) = Jν (βx) and h(t) =... of equation 4.9.1 with g(x) = cosm (µx) and h(t) = tanhk (βt) b 44 tanhk (βx) sinm (µt)y(t) dt = f (x) y(x) – λ a This is a special case of equation 4.9.1 with g(x) = tanhk (βx) and h(t) = sinm (µt) b 45 tanhk (βt) sinm (µx)y(t) dt = f (x) y(x) – λ a This is a special case of equation 4.9.1 with g(x) = sinm (µx) and h(t) = tanhk (βt) 4.7-6 Kernels Containing Logarithmic and Trigonometric Functions b . (x). This is a special case of equation 4.9.10 with h(x) = cot(βx). 4 .5- 5. Kernels Containing Combinations of Trigonometric Functions 54 . y(x) – λ  b a cos k (βx) sin m (µt)y(t) dt = f (x). This is. that y  xx (x)+σ n y(x) – n  k=1 A k λ 2 k I k = f  xx (x), σ n =2 n  k=1 A k λ k . (5) Eliminating the integral I n from (4) and (5) yields y  xx (x)+(σ n + λ 2 n )y(x)+ n–1  k=1 A k (λ 2 n – λ 2 k )I k =. I. Cherskii (1978). 4 .5- 3. Kernels Containing Tangent 34. y(x) – λ  b a tan(βx)y(t) dt = f (x). This is a special case of equation 4.9.1 with g(x) = tan(βx) and h(t)=1. 35. y(x) – λ  b a tan(βt)y(t)

Ngày đăng: 23/07/2014, 16:20