THEOREM 9.5. Let X be a Hilbert space and let A: X₁, X₂, ... be an orthonormal set in X. Then, if EF (n = 1, 2, ...), we have (1) Σ1%* converges if and only if Σ=₁ |α₂|² < ∞, and (2) if Σ₁%,* converges to x, then α = (x, xn). =1 Proof (2). Consider makking from *x to F x = 2 an n=1 S₂ = 24x₁. α; = (Sn, xj). Since this relationship is true (that is, the value remains the same) for any n> j, it must also be true in the limit, and we can write and the partial sum For n>j, we define Request explain the underlined parts Thm 9.2 это Xis an lim(S₁, xj) = αj. n mer product space, Appealing to Theorem 9.2, we can assert the continuity of the inner product mapping which allows us to interchange the operations of limit and inner product e inver product in the above equation, which yields _n,Y) is a continuous (x, xj) = αj, which is the desired result. Thus, knowing that the given series converges to some x, we have a strong relationship between the coefficients in the series and x.
THEOREM 9.5. Let X be a Hilbert space and let A: X₁, X₂, ... be an orthonormal set in X. Then, if EF (n = 1, 2, ...), we have (1) Σ1%* converges if and only if Σ=₁ |α₂|² < ∞, and (2) if Σ₁%,* converges to x, then α = (x, xn). =1 Proof (2). Consider makking from *x to F x = 2 an n=1 S₂ = 24x₁. α; = (Sn, xj). Since this relationship is true (that is, the value remains the same) for any n> j, it must also be true in the limit, and we can write and the partial sum For n>j, we define Request explain the underlined parts Thm 9.2 это Xis an lim(S₁, xj) = αj. n mer product space, Appealing to Theorem 9.2, we can assert the continuity of the inner product mapping which allows us to interchange the operations of limit and inner product e inver product in the above equation, which yields _n,Y) is a continuous (x, xj) = αj, which is the desired result. Thus, knowing that the given series converges to some x, we have a strong relationship between the coefficients in the series and x.
Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
Related questions
Question
100%
Expert Solution
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
Step by step
Solved in 2 steps with 2 images
Similar questions
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,