Proposition 2. (Comparison Test for improper integrals) Let f(t) and g(t) be functions on the domain (0,0). Suppose first that f(t) < g(t) for all t>a, and that g(t)dt converges. Then fa f(t)dt converges. Similarly, suppose that f(t) < g(t) for all t>a, and that f f(t)dt diverges. Then g(t)dt diverges. (You should think for a minute about why these should intuitively be true.) Problem 7: A) A function is of exponential type if there exists constants C, M and to with M> 0 not depending on t such that for all t > to, |ƒ(t)| < Met. Prove that if a function f(t) is piece-wise continuous on [0, ∞] and is of exponential type with constants M and C as above, then (L{f})(s) exists for all s > C. (Hint: first, get rid of a "finite" part of the integral, then use the above proposition.) B) Show that f(t) = et² is not of exponential type. (Hint: for any C>0, t² - Ct > 0 for all t> C. p(t) C) Show that for any C> 0 and any polynomial p(t), lim = 0. Note that this implies that p(x) is of exponential type. t-x Problem 8: Show that if f(t) is a function of exponential type (i.e. the Laplace Transform of f(t) actually exists), then (L{f'(t)})(s) = s(L{f})(s) — ƒ(0). (Hint: integration by parts.)

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Topic Video
Question

Please explain each step of getting this answer clearly, Don't just show the answer. 

Proposition 2. (Comparison Test for improper integrals) Let f(t) and g(t) be functions on the
domain (0, 0). Suppose first that f(t) < g(t) for all t > a, and that º g(t)dt converges. Then
Sa f(t)dt converges. Similarly, suppose that f(t) < g(t) for all t > a, and that f(t)dt diverges.
Then g(t)dt diverges.
(You should think for a minute about why these should intuitively be true.)
Problem 7: A) A function is of exponential type if there exists constants C, M and to with M > 0
not depending on t such that for all t > to, |f(t)| < MeCt. Prove that if a function f(t) is piece-wise
continuous on [0, ∞] and is of exponential type with constants M and C as above, then (L{f})(s)
exists for all s > C. (Hint: first, get rid of a "finite" part of the integral, then use the above
proposition.)
B) Show that f(t) = e² is not of exponential type. (Hint: for any C > 0, t² – Ct > 0 for all
t >C.
C) Show that for any C > 0 and any polynomial p(t), lim 2 = 0. Note that this implies
that p(x) is of exponential type.
Problem 8: Show that if f(t) is a function of exponential type (i.e. the Laplace Transform of f(t)
actually exists), then (L{f'(t)})(s) = s(L{f})(s) – f(0). (Hint: integration by parts.)
Transcribed Image Text:Proposition 2. (Comparison Test for improper integrals) Let f(t) and g(t) be functions on the domain (0, 0). Suppose first that f(t) < g(t) for all t > a, and that º g(t)dt converges. Then Sa f(t)dt converges. Similarly, suppose that f(t) < g(t) for all t > a, and that f(t)dt diverges. Then g(t)dt diverges. (You should think for a minute about why these should intuitively be true.) Problem 7: A) A function is of exponential type if there exists constants C, M and to with M > 0 not depending on t such that for all t > to, |f(t)| < MeCt. Prove that if a function f(t) is piece-wise continuous on [0, ∞] and is of exponential type with constants M and C as above, then (L{f})(s) exists for all s > C. (Hint: first, get rid of a "finite" part of the integral, then use the above proposition.) B) Show that f(t) = e² is not of exponential type. (Hint: for any C > 0, t² – Ct > 0 for all t >C. C) Show that for any C > 0 and any polynomial p(t), lim 2 = 0. Note that this implies that p(x) is of exponential type. Problem 8: Show that if f(t) is a function of exponential type (i.e. the Laplace Transform of f(t) actually exists), then (L{f'(t)})(s) = s(L{f})(s) – f(0). (Hint: integration by parts.)
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 4 steps

Blurred answer
Knowledge Booster
Research Design Formulation
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, advanced-math and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
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…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,