Begin2.DVI

(Ben Green) #1
10-39. Show the relation between the vector differential equation

d ̄y
dt =A(t) ̄y+
f ̄(t), y ̄(0) = ̄c

and the matrix differential equation

dY
dt =A(t)Y, Y (0) = I

is given by

y ̄=Y(t) ̄c+Y(t)

∫t

0

Y−^1 (ξ)f ̄(ξ)dξ

10-40. Verify the forward differences in table 10.1.

10-41. Verify the finite integrals in table 10.2.

10-42. Solve the given difference equations.

(a) yn+2 − 5 yn+1 + 6yn= 0
(b) yn+2 − 6 yn+1 + 9yn= 0
(c) yn+2 − 6 yn+1 + 13yn= 0

(d) yn+2 + 4yn+1 + 3 yn= 0
(e) yn+2 + 2yn+1 +yn= 0
(f) yn+2 + 2yn+1 + 10 yn= 0

10-43. Find the finite integrals

(a) ∆ −^1 x^2 (b) ∆ −^11
(3 + 2x)n

(c) ∆ −^11
xn

10-44.


(a) For A=

[
2 0
1 3

]

, verify the matrix function eAt =

[
e^2 t 0
e^3 t−e^2 t e^3 t

]

(b) For B=

[
2 1
0 1

]

, verify the matrix function eBt =

[
e^2 t e^2 t−et
0 et

]

10-45.


(a) Verify the matrix differential equation

dX (t)
dt

=AX (t) + F(t), X (0) = C

has the matrix solution

X=X(t) = eAtC+eAt

∫t

0

e−Aξ F(ξ)dξ

(b) For A=

[
2 0
1 3

]

,F(t) =

[
et
1

]

and C=

[
1
0

]

solve the matrix differential equation

dX (t)
dt =AX +F(t), X (0) = C
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