A model of tumour growth under chemotherapy from time t = 0 to t = t₁ > 0 is dC dt = -Clog ( C Cmax equation (*) becomes dx dt where, at time t, C(t) is the size of the tumour, Cmax > 0 is the maximum size of the tumour, a constant, so that 0 < C(t) ≤ Cmax, and D(t) ≥ 0 is the rate at which the drug is administered. x = log(C/Cmax), =-x- where D 1+ D' rt₁ S[x] = - " where - < x≤0. t = t₁. Let co = It is required to reduce the size of the tumour from Co at t = 0 to C₁ at log(Co/Cmax) and x₁ log(C₁/Cmax). For the health of the patient, it is desired to minimise the total amount of drug administered, which is given by the functional S[D] = [ª dt D(t). α= DC 1+D - dt x + x 1+x+x Euler-Lagrange equation for S[x] is given by -t x(t) = = ae + (xo + 1 − a)e¯t/2 – 1, (*) 2x + 3x + x = −1 where = d²x/dt². Solve (**) with the boundary conditions x(0) = xo and x(t₁) = x₁, to show that the stationary path of S[x] is given by (xo + 1)e−t₁/² − (x₁ + 1) e-t₁/2 - e-ti (**)

College Algebra
1st Edition
ISBN:9781938168383
Author:Jay Abramson
Publisher:Jay Abramson
Chapter6: Exponential And Logarithmic Functions
Section6.8: Fitting Exponential Models To Data
Problem 1TI: Table 2 shows a recent graduate’s credit card balance each month after graduation. a. Use...
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A model of tumour growth under chemotherapy from time t = 0 to
t = t₁> 0 is
-C log
where, at time t, C(t) is the size of the tumour, Cmax > 0 is the maximum
size of the tumour, a constant, so that 0 <C(t) ≤ Cmax, and D(t) > 0 is the
rate at which the drug is administered.
dC
dt
equation (*) becomes
dx
dt
=-X
C
Cmax
rt₁
S[D] = fª dt D(t).
S[x] = -
D
1+ D'
where
where ·∞ < x≤ 0.
It is required to reduce the size of the tumour from Co at t = 0 to C₁ at
t = t₁. Let x = log(Co/Cmax) and x₁ = log(C1₁/Cmax). For the health of the
patient, it is desired to minimise the total amount of drug administered,
which is given by the functional
rt₁
["d
α=
dt
DC
1+ D
2x + 3x + x = -1
x + x
1 + x + x
x = log(C/Cmax),
Euler-Lagrange equation for S[x] is given by
where x = d²x/dt².
Solve (**) with the boundary conditions x(0) = x₁ and x(t₁) = x1, to
show that the stationary path of S[x] is given by
x(t) = aet+ (xo +1-a)e-t/2 - 1,
(x + 1)e−t₁/² − (x₁ +1)
e-t₁/2 - e-ti
(*)
(**)
Transcribed Image Text:A model of tumour growth under chemotherapy from time t = 0 to t = t₁> 0 is -C log where, at time t, C(t) is the size of the tumour, Cmax > 0 is the maximum size of the tumour, a constant, so that 0 <C(t) ≤ Cmax, and D(t) > 0 is the rate at which the drug is administered. dC dt equation (*) becomes dx dt =-X C Cmax rt₁ S[D] = fª dt D(t). S[x] = - D 1+ D' where where ·∞ < x≤ 0. It is required to reduce the size of the tumour from Co at t = 0 to C₁ at t = t₁. Let x = log(Co/Cmax) and x₁ = log(C1₁/Cmax). For the health of the patient, it is desired to minimise the total amount of drug administered, which is given by the functional rt₁ ["d α= dt DC 1+ D 2x + 3x + x = -1 x + x 1 + x + x x = log(C/Cmax), Euler-Lagrange equation for S[x] is given by where x = d²x/dt². Solve (**) with the boundary conditions x(0) = x₁ and x(t₁) = x1, to show that the stationary path of S[x] is given by x(t) = aet+ (xo +1-a)e-t/2 - 1, (x + 1)e−t₁/² − (x₁ +1) e-t₁/2 - e-ti (*) (**)
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