Consider a system with the input/output relationship y(t) =
x(t)cos(15πt).
(a) Is this system (i) linear, (ii) causal, (iii) stable, (iv)
memoryless, (v) time-invariant, and (vi) invertible. Justify each
answer with a clear mathematical argument. (b) Find the Fourier
Transform Y (f) of y(t) in terms of the transform X(f) of x(t).
Repeat problem (2) for the system with the input-output
relationship y(t) =R1 τ=0(1−τ)2x(t−τ)dτ.
1. Let X and Y be non-linear spaces and T : X -->Y. Prove
that if T is One-to-one then T-1 exist
on R(T) and T-1 : R(T) à X is also a linear map.
2. Let X, Y and Z be linear spaces over the scalar field F, and
let T1 ϵ B (X, Y) and T2 ϵ B (Y, Z). let
T1T2(x) = T2(T1x)
∀ x ϵ X.
(i) Prove that T1T2 ϵ B
(X,Y) is also a...
Let M(x, y) be "x has sent y an e-mail message" and T(x, y) be "
x has telephoned y, " where the domain consists of all students in
your class. Use quantifiers to express each of these
statements.
g. There is a student in your class who sent every one else in
your class an email message.
I answer ∃x( x ≠ y ∧ ∀? M (x, y) )
But answer on text book is ∃x( x ≠ y → ∀?...
let a be a non zero constant and consider: y''+(1/t)y'=a
a. show that 1 and ln(t) are linear independent solutions of the
corresponding homogenous equation
b. using variation of parameters find the particular solution to
the non homogenous equation
c. express the solution to the non homogenous equation in terms
of a. and b.
d.since y itself does not appear in the equation, the
substitution w=y' can be used to reduce the equation to a linear
1st order equation. use...
Let X, Y ⊂ Z and x, y ∈ Z Let A = (X\{x}) ∪ {x}.
a) Prove or disprove: A ⊆ X
b) Prove or disprove: X ⊆ A
c) Prove or disprove: P(X ∪ Y ) ⊆ P(X) ∪ P(Y ) ∪ P(X ∩ Y )
d) Prove or disprove: P(X) ∪ P(Y ) ∪ P(X ∩ Y ) ⊆ P(X ∪ Y )
Let X ~ exp(λ)
MGF of X = λ/(1-t)
a) What is MGF of Y = 3X
b) Y has a common distribution, what is the pdf of Y?
c) Let X1,X2,....Xk be independent and identically distributed
with Xi ~ exp(λ) and S = Σ Xi (with i = 1 below
the summation symbol, and k is on top of the summation symbol).
What is the MGF of S?
d) S has a common distribution. What is the pdf of...
Let y(t) = (1 + t)^2 solution of the
differential equation y´´ (t) + p (t) y´ (t) + q (t) y (t) = 0
(*)
If the Wronskian of two solutions of (*) equals three.
(a) ffind p(t) and q(t)
(b) Solve y´´ (t) + p (t) y´ (t) + q (t) y (t) = 1 + t