Question : Find a constant solution of y' = t(y - 1). Enter just an integer. : 2163497
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
1) Find a constant solution of y' = t(y - 1).
Enter just an integer.
2) Find a constant solution of y' = 10 y - 7.
Enter just a reduced fraction of form (a/b).
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
3) Consider the differential equation y' = t3(y + 3). Which of the following statements is/are true?
(I) f(t) = -3 is a constant solution to this differential equation.
(II) f(t) = 0 is a constant solution to this differential equation.
(III) If f(t) is a solution to the differential equation with initial conditions y(1) = 0, then f '(1) = 3.
A) II only
B) III only
C) I only
D) I, II, and III
E) I and III
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
4) Find f'(1) if f(t) is a solution to the initial value problem: y' = ty2 + 5, y(1) = 1.
Enter just an integer.
5) Find f'(0) if f(t) is a solution to the initial value problem: y' = e2t + y, y(0) = -1.
Enter just an integer.
6) Find f'(1) if f(t) is a solution to the initial value problem: y' = e2t - y, y(1) = 0.
Enter just a real number (no approximations).
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
7) Consider the differential equation y' = y - y2. Which of the following statements is/are true?
A) If f(t) is a solution to the differential equation satisfying the initial condition y(0) = 0, then f '(0) = 0.
B) This differential equation has infinitely many solutions.
C) The function f(t) = (1/(1 + e-t)) is a solution to this differential equation with initial condition y(0) = (1/2).
D) The constant function f(t) = 1 is a solution to this differential equation.
E) All of these statements are true.
Solve the problem.
8) Write a differential equation that expresses the following description of a rate: When ice cream is removed from the freezer, it warms up at a rate proportional to the difference between the temperature of the ice cream and the room temperature of 76°. (Use y for the temperature of the ice cream, t for the time, and k for an unknown constant.)
A) y' = k(76 - t)
B) y' = 76 - ky
C) y' = 76t - ky
D) y' = k(76 - y)
9) The growth rate of a certain stock is modeled by (dV/dt) = k(44 - V), V = $21 when t = 0, where V = the value of the stock, per share, after time t (in months), and k = a constant. Find the solution to the differential equation in terms of t and k.
A) V = 44 - 44e-kt
B) V = 44 - 23e-kt
C) V = 21 - 23e-kt
D) V = 44 - 23ekt
10) Solve the differential equation model of radioactive decay:
(dQ/dt) = -0.3Q.
A) Q(t) = -Q0ln0.3t + c
B) Q(t) = Q0e-t
C) Q(t) = (-1/0.3t) + Q0
D) Q(t) = Q0e-0.3t
11) Sales (in thousands) of a certain product are declining at a rate proportional to the amount of sales, with a decay constant of 11% per year. Write a differential equation to express the rate of sales decline.
A) dy/dt = -0.11y
B) dy/dt = -0.89y
C) dy/dt = e-0.11t
D) dy/dt = -0.11t
12) Which of the following functions solves the differential equation: y' = -4y?
A) y = - e-4t
B) y = e-4t
C) y = ln4t
D) none of these
13) Which of the following functions solves the differential equation: y' = e-2x + 3?
A) y = e-2x + 3
B) y = (1/2)e-2x + 3
C) y = - (1/2)e-2x + 3x
D) none of these
14) Which of the following functions solves the differential equation: y' = -6xy?
A) y = e-x^2
B) y = 7e-x^2
C) y = e-3x^2
D) y = 7e-3x^2
15) Which of the following functions solves the differential equation: y' = y2?
A) y = ln|1 + x|
B) y = (1/3)x3
C) y = - (1/x2)
D) y = - (1/x + 1)
Use the figure to answer the question.
16) The figure shows a slope field of the differential equation y' = 5y(5 - y). Use the figure to determine the constant solutions (if any) of the differential equation.
A) y = -5, y = 5
B) y = 0, y = 5
C) None
D) y = 0
17) The figure shows a slope field for the differential equation y' = t - y. Draw an approximation of a portion of the solution curve for y' = t - y that goes through the point (0, 2). Based on the slope field, can this solution pass through the point (1.1, 0.4)?
A) No
B) Yes
C) Yes
D) No