MAE 215: Introduction to Programming in MATLAB, Fall 2016
Homework Assignment #2
Due: Tuesday, September 20th by 11.59 pm
Submission Instructions: Your solutions to this assignment must be typed and neatly
presented. Unorganized solutions and/or solutions that do not present the required
deliverables will not be graded and receive a score of zero. This assignment is to be
submitted, in PDF format, to the assignment link on blackboard by the deadline.
– Students who obtain a score of 80% or greater on problems #2 and #3 will receive credit for
outcome #1: students will demonstrate proficiency in the use of common MATLAB functions.
– Well organized homework submitted as M-file that can be compiled and run to show the
answers will be awarded extra points.
1. [10 pts] Working with MATLAB scalars, vectors, and complex numbers.
Using MATLAB, define a unique variable for the following quantities.
a. 5 (ex. Define x = 5, etc.)
b. 252
c. (3 + 4) + 82
d. √36 + 72
e.
f.
g.
h.
i.
j.

72

5 +6.54
the area of a circle of radius 11.21
the circumference of the same circle in (f)
the area of a square with side length 7.81
the side length of a cube of volume 107.81.
the magnitude of the vector in (c) (hint: look into real(), imag() or abs())

2. [25 pts] Using built-in functions to manipulate MATLAB variables.
a. define the following vector: (problems a – f)
= < √15, 13,34,72 , √54, 89.2,0.541, 7/8 , 10, log10 34.2 >
b. what is the max and minimum value of the above vector? In what elements are
these values found?
c. find the square root, cube root and 7th root of this vector using a single operation.
d. what is the length of the vector? How many elements does it have? (you must use
MATLAB to determine/prove this)
e. Replace the max value of the vector with a value 8.1x its size without redefining
the entire vector. Do the same with the minimum value.
f. create a new, unique, vector containing the 3rd, 7th and last values of the vector in
(a).
g. define a vector from 0 to 10 with 100 equally spaced entries (hint: look at
linspace)
h. define a vector ranging from 110 to 120 with a step size of 0.1. What is the length
of the resulting vector?
i. evaluate the trigonometric functions sin and cos from 0 to 2 radians in steps of
0.1.

j. consider the following vector:
2 3 4 5 6 7 8
< 1, , , , , , , , >
2! 3! 4! 5! 6! 7! 8!
define this vector in matlab for a user-selected value of x. Find a MATLAB function
that will sum the entries of this vector together. Compare your answer to
MATLAB’s exp(x) for the same value of x. Are your answers reasonably close?
What does the built-in function you found appear to do?
k. define a random 100 x 1 vector (be sure to suppress the output). What are the
mean, median and mode? (hint: use rand(m,n)).
3. [25 pts] Understanding MATLAB matrices.
a. define the following matrices in MATLAB: (problems a – g)
6 5 1
= [12 2 0]
2 1 6
= [6, 17, 8]
b. what are the eigenvalues of A (hint: eig())? What is the determinant of A? (find a
MATLAB function that can do this for you) What is A-1?
c. Replace the max and min values of A with the values of a11 and a12, respectively.
d. Create a new matrix from the last two rows of A and the vector B without
redefining the system.
e. what is the sum of the first row of A? First column of A?
f. How many elements are in A? B? (must use MATLAB to prove result) Multiply
each element in A by 7.2 and each element in B by 2. Find a way to multiply
matrices A and B. What must you do? How did you accomplish this?
g. Flip the vector B from right to left. Transpose the matrix into a column vector and
flip it once again from up to down.
h. define a random 6×6 matrix, a 3×3 matrix of zeros, 3×3 matrix of ones and the 4×4
identity matrix. (hint: use built-in MATLAB functions). Find a way to combine the
random 6×6 matrix, the matrix of ones and the matrix of zeros into a single, 6×9
matrix. (hint: this will likely be a 2 step process).
i. create (another) random 8×8 matrix (be sure to suppress the output). Find a way
to define two separate, smaller, 4×4 matrices composed of the values from the “top
left” and “bottom right” sub-matrices of the larger, 8×8.
j. Consider the vectors <3,7,1> and <5,2,0>. Find the unit vector of each, a vector
normal to both, and the dot product of the two. (hint: look for built-in functions).