MATH2021: Vector Calculus and Differential Equations
Vector Calculus and Differential Equations
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MATH2021: Vector Calculus and Differential Equations
This individual assignment is due by 11:59pm Thursday 12 May 2022, via
Canvas. Late assignments will receive a penalty of 5% per day until the closing date.
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some collaboration between students whenworking on problems, but students must
write up and submit their own version of the solutions.
This assignment is worth 5% of your final assessment for this course. Your answers should be
well written, neat, thoughtful, mathematically concise, and a pleasure to read. Please cite any
resources used and show all working. Present your arguments clearly using words of explanation
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Mark Grade Criterion
8 A Outstanding and scholarly work, answering all parts correctly, with clear
accurate explanations and all relevant diagrams and working. There are
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7 B Very good work, making excellent progress, but with one or two substantial
errors, misunderstandings or omissions throughout the assignment.
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substantial errors, misunderstandings or omissions throughout the assign-
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3 E Some attempt, with limited progress made.
1 F Extremely limited attempt.
0 Z No credit awarded.
Copyright c© 2022 The University of Sydney 1
The University of Sydney
School of Mathematics and Statistics
Assignment 2
MATH2021: Vector Calculus and Differential Equations Semester 1, 2022
Lecturer: James Parkinson, Fernando Viera
Differential Equations
Exact Equations
1. Construct an Exact equation that is satisfied by the function
F (x, y) = cos(x)esin(xy)
2. Show that F (x, y) = x2y + exy (1) is a solution of the equation
y
(
2x + exy
)
dx + x
(
x + exy
)
dy = 0
Separable Equations
3. Which of the following differential equations are Separable? Solve the ones that are
separable:
(a) (1 + x)
dy
dx
+ y2 = 0
(b) y
dy
dx
= (x− y2) sin y
(c)
dy
dx
=
x + 1
2xy
Linear First Order Equations
4. Solve the following Linear First Order Equation using the Integrating Factor Method:
(1 + x2)
dy
dx
= 1− 2xy.
5. Use the method of Variation of Parameters to find the general solution of the following
linear first order equation:
dy
dx
− 3y = xe−x.