Concept explainers
For each of these arguments, explain which rules of inference are used for each step.
a) "Linda, a student in this class, owns a red convertible. Everyone who owns a red convertible has gotten at least one speeding ticket. Therefore, someone in this class has gotten a speeding ticket."
b) "Each of five roommates, Melissa, Ralph, Veneesha, and Keeshawn, has taken a course in discrete mathematics. Every student who has taken a course in discrete mathematics can take a course in Therefore, all five roommates can take a course in next year."
c) "All produced by John Sayles are wonderful. John Sayles produced a movie about coal miners. Therefore, there is a wonderful movie about coal miners."
d) "There is someone in this class who has been to France. Everyone who goes to France visits the Louvre. Therefore, someone in this class has visited the Louvre.”
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Chapter 1 Solutions
DISCRETE MATH
- 7. (a) (i) Express y=-x²-7x-15 in the form y = −(x+p)²+q. (ii) Hence, sketch the graph of y=-x²-7x-15. (b) (i) Express y = x² - 3x + 4 in the form y = (x − p)²+q. (ii) Hence, sketch the graph of y = x² - 3x + 4. 28 CHAPTER 1arrow_forward- (c) Suppose V is a solution to the PDE V₁ – V× = 0 and W is a solution to the PDE W₁+2Wx = 0. (i) Prove that both V and W are solutions to the following 2nd order PDE Utt Utx2Uxx = 0. (ii) Find the general solutions to the 2nd order PDE (1) from part c(i). (1)arrow_forwardSolve the following inhomogeneous wave equation with initial data. Utt-Uxx = 2, x = R U(x, 0) = 0 Ut(x, 0): = COS Xarrow_forward
- Could you please solve this question on a note book. please dont use AI because this is the third time i upload it and they send an AI answer. If you cant solve handwritten dont use the question send it back. Thank you.arrow_forward(a) Write down the general solutions for the wave equation Utt - Uxx = 0. (b) Solve the following Goursat problem Utt-Uxx = 0, x = R Ux-t=0 = 4x2 Ux+t=0 = 0 (c) Describe the domain of influence and domain of dependence for wave equations. (d) Solve the following inhomogeneous wave equation with initial data. Utt - Uxx = 2, x ЄR U(x, 0) = 0 Ut(x, 0) = COS Xarrow_forwardQuestion 3 (a) Find the principal part of the PDE AU + Ux +U₁ + x + y = 0 and determine whether it's hyperbolic, elliptic or parabolic. (b) Prove that if U (r, 0) solves the Laplace equation in R2, then so is V (r, 0) = U (², −0). (c) Find the harmonic function on the annular region 2 = {1 < r < 2} satisfying the boundary conditions given by U(1, 0) = 1, U(2, 0) = 1 + 15 sin(20).arrow_forward
- 1c pleasearrow_forwardQuestion 4 (a) Find all possible values of a, b such that [sin(ax)]ebt solves the heat equation U₁ = Uxx, x > 0. (b) Consider the solution U(x,t) = (sin x)e¯t of the heat equation U₁ = Uxx. Find the location of its maxima and minima in the rectangle Π {0≤ x ≤ 1, 0 ≤t≤T} 00} (explain your reasonings for every steps). U₁ = Uxxx>0 Ux(0,t) = 0 U(x, 0) = −1arrow_forwardCould you please solve this question on a note book. please dont use AI because this is the third time i upload it and they send an AI answer. If you cant solve handwritten dont use the question send it back. Thank you.arrow_forward
- Could you please solve this question on a note book. please dont use AI because this is the third time i upload it and they send an AI answer. If you cant solve handwritten dont use the question send it back. Thank you.arrow_forward(b) Consider the equation Ux - 2Ut = -3. (i) Find the characteristics of this equation. (ii) Find the general solutions of this equation. (iii) Solve the following initial value problem for this equation Ux - 2U₁ = −3 U(x, 0) = 0.arrow_forwardQuestion 4 (a) Find all possible values of a, b such that [sin(ax)]ebt solves the heat equation U₁ = Uxx, x > 0. (b) Consider the solution U(x,t) = (sin x)et of the heat equation U₁ = Uxx. Find the location of its maxima and minima in the rectangle πT {0≤ x ≤½,0≤ t≤T} 2' (c) Solve the following heat equation with boundary and initial condition on the half line {x>0} (explain your reasonings for every steps). Ut = Uxx, x > 0 Ux(0,t) = 0 U(x, 0) = = =1 [4] [6] [10]arrow_forward
- Elementary Geometry for College StudentsGeometryISBN:9781285195698Author:Daniel C. Alexander, Geralyn M. KoeberleinPublisher:Cengage LearningElementary Geometry For College Students, 7eGeometryISBN:9781337614085Author:Alexander, Daniel C.; Koeberlein, Geralyn M.Publisher:Cengage,