2015F001/Homework5

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  1. What output results from running the following Matlab code?
  2. Matlab Assignment
  3. Without running Matlab, what output results from running the following Matlab code?
  4. Use Matlab to evaluate the following expressions.
  5. Variables are programmer-designated names that can represent a specific value of data. Like other programming languages, MATLAB also has a set of rules for naming variables. If the rules are violated, the variables can not be treated as valid variables, causing programming errors.
  6. Anonymous function in Matlab
  7. Suppose that you have defined the function foo as follows
  8. Write a Matlab function (m file) to evaluate the function logfunc(x, y) = log10(x2) - log10(y2)

1. What output results from running the following Matlab code?

a = 1 + 2 * (3 \( 4*(5 - 6/3)));
a = a * a
b = -1*a/9
c = b^2 - 25.0 
d = a - b + c*c 
display (a)


a =81

b =-9

c =56

d =3226

a =81

2. Matlab Assignment

Create a variable called m and assign to it the value 1.0. Then create the following variables and assign to them the following values:


n m squared minus 3

p m cubed minus the cosine of m

q m divided by the cube of the quantity m squared plus 1

r negative two plus the square root of m

s the cosine of the following quantity: n divided by the quantity p plus r


Matlab code:

m= 1.0;
n= (m^2)-3;
p=(m^3)-cos(m);
q= m/((m^2)+1)^3;
r= -2+(m^2);
s= cos(n/(p+r))

3. Without running Matlab, what output results from running the following Matlab code?

%% A matlab code to test arithmetic functions. 
a = 0.0;
b = 4.0;

a = a + 2; 
b = a + 2; 
a = sqrt(a) + a ; 
b = a + b\2; 
b = ceil (b); 
a = round (a);
c = mod (a, round(b));
a
b
c


Ans:

    a= 4
    b= 5
    c= 1

4. Use Matlab to evaluate the following expressions.

  1. \sqrt { 2 } \pi ^ 4
  2.  \frac {\pi } {\sin (2.0) * \cos (0.5)}
  3.  (0.0000123 + pi \times 10 ^{-3} ) \times 0.567 \times 10.1 ^ {-4}
  4.  \mod (5, 4)
  5.  \mod (2, 5)
  6. floor( − 7.6)
  7. ceil(3.4)
  8. round(5.5)

Ans=

  1. 137.7573
  2. 3.9369
  3. 1.7185e-07
  4. 1
  5. 2
  6. -8
  7. 4
  8. 6

5. Variables are programmer-designated names that can represent a specific value of data. Like other programming languages, MATLAB also has a set of rules for naming variables. If the rules are violated, the variables can not be treated as valid variables, causing programming errors.

Create four "invalid" variable names with different reasons, and state the reason why the variable names can not be used in MATLAB.


  2eee2e2     it starts with a number
  e four      it can't have a space
  King-dedede it can't have a hyphen
  BBB*F       it can't have a multiplication symbol

6. Anonymous function in Matlab

An anonymous function defined in matlab is a function that is not stored in a program file, but associated with a variable. Provide a matlab script in which a mathematical function f(x,y) is defined as

f(x,y) = cos(x3) + sin(y3) + ex-y

Calculate the values of f(0.3,0.2), f(3,2), f(π, π / 2) using the defined anonymous function in Matlab.

7. Suppose that you have defined the function foo as follows

function y = foo(x)
z = x / 2; 
y = x - z^2; 
end

what are the values from the following calls?

>> foo(2)= 1

>> foo(foo(2))= 0.7500

8. Write a Matlab function (m file) to evaluate the function logfunc(x, y) = log10(x2) - log10(y2)

(1) show your m-file for this function;

 f= @(x,y) log10(x^2)-log10(y^2)

(2) calculate logfunc(3, 2) and logfunc(-5, -3)

   0.3522    and   0.4437
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