MATLAB Basic Programming

What will the statement "myNum = 2 + 2" store in myNum?

4

Suppose you want to automatically generate a vector of with 2 entries; the 1st entry starting at 0 and ends at 1. How would you create this vector in MATLAB?

x = linspace(0,1,2)

Whats another way to do this?

0:1:2

Now Suppose you want to automatically generate a vector of 11 entries; the 1st entry starting at 0 and ends at 1. How would you create this vector in MATLAB?

x = linspace(0,1,11)

Whats another way to do this?

0:1:11

Now Suppose you want to automatically generate a vector with 8 entries; the 1st entry starting at 0 and ends at 3. How would you create this vector in MATLAB?

x = linspace(0,3,8) or x = 0:3:8

How would you access the first twelve elements for y?

y = (1:12);

x(1:12)

OR

y = (1:12);

x(1:12)

How would you access the 1st four multiples of 3 specified in a vector?

y([3 6 9 12])

Write a statement transposing x

x'

Write two statements that notes the difference in tranpose of z

z' and z.'

Elementary functions in MATLAB

Use the following few commands (a script) to make a plot. The evaluation of v=cos(u) creates a vector whose elements are:

v(k) = cos(u(k)) where k = 1, 2, ...n

n = anu number;

u = linspace(0, 2pin);

v = cos(u);

plot(u,v)

How would you clean up this plot?

By plotting axis label and a title; the text inside the single quotes is a string which we intend to be the labels.

xlabel('u');

ylabel('v');

title('v = cos(u)');

command "help plot" would be very helpful

Write a statement that would transpose a 3x4 matrix

x = [1 2 3 4; 5 6 7 8; 9 10 11 12];

x'

x =

1 2 3 4

5 6 7 8

9 10 11 12

ans =

1 5 9

2 6 10

3 7 11

4 8 12

If the previously-entered statement was "num1 = 5", what value will be stored in num2 after the statements "num1 = num1 + num1" followed by "num2 = num1 + 3".

13;;

The interpreter computes 5 + 5, which is 10, then stores 10 in num1. The interpreter then computes num1 + 3, which is 10 + 3 or 13, and stores 13 in num2.

If the previously-entered statement was "num1 = 9", what value will be stored in num2 after the statement "num2 = num1 * num1"?

81

If all previous statements dealt only with num1, num2, and num3, what value will the statement "num4" print?

error

If all previous statements dealt only with num1, num2, and num3, what value will the statement "num4" print?

error

What symbol at the end of a statement suppresses printing of the result?

; (semicolon)

Test your understanding of what will be output to the command window as a result of entering the following lines.

1)

X = 14; Y = 2, Z = 5

Only X will display.

Only Y and Z will display.

None of the above.

Only Y and Z will display.

The semicolon suppresses the output of X, commas do not suppress output.

C = 100 K = C + 273

Only C will display.

Both C and K will display.

The statement results in an error.

Statements must be separated by a semicolon or comma, else the line is treated as one statement, which in this case is not a valid statement, yielding an error.

Matt Labler is a novice MATLAB programmer. He wants to set variable A to 6, B to 9, and C to their sum, with only the values of A and C displaying in the command window. He asks you to check the following statement for bugs: A = 6; B = 9; C = A + B

The code is correct as is.

Matt should use "A = 6, B = 9; C = A + B" instead.

Matt should use "A =6; B = 9, C = A + B;" instead.

Matt should use "A = 6, B = 9; C = A + B" instead.

X = 39; Y = 41, Z = X + 17

The statement results in an error.

Only Y is displayed.

Only Y and Z are displayed.

only Y and Z displayed

Matlab challenge activities

Multiply x by 2 and put the result in y.

Ex: If x is 2, then output y should be 4.

x=2;

y=x+2

A bit is a 0 or 1, interpreted from voltage.

True

False

true

1 is usually a higher voltage (e.g., 2.0 V), 0 is usually a lower voltage (e.g., 0 V).

A processor is a circuit that executes instructions.

True

False

true

A memory is a circuit that stores one machine instruction.

True

False

false

An assembler translates an assembly program into machine instructions.

True

False

true

A high-level language eases a programmer's task of writing complex programs.

true

See PARTICIPATION

ACTIVITY

1.5.2: Binary numbers.

Defining numeric variables.

1)

Write a variable assignment statement that assigns totalPets with 3.

totalPets = 3;

or

totalPets = 3

Write a variable assignment statement that assigns luckyNumber with 7 and suppresses the output to the command window.

luckyNumber = 7;

Write a variable assignment statement that assigns birdFeeders with the current value of variable stockCount, and prints the value of the variable to the command window.

birdFeeders = stockCount

What is the value stored in luckyNumber after these two statements execute?

luckyNumber = 7;

luckyNumber = 4;

4

The second write to luckyNumber overwrites the first value written into the variable.

Assume apples currently has the value 5 and oranges the value 9. What is the value stored in apples after the following statement?

apples = apples + 1;

6

5 + 1 yields 6

Assume apples currently has the value 5 and oranges the value 9. What is the value stored in apples after the following statements?

apples = oranges;

oranges = oranges + 1;

9

Write a statement, ending with "- 1;", that decreases the value stored in apples by 1.

apples = apples - 1;

Write two statements, the first setting apples to 7, and the second setting oranges to apples plus one. Terminate each statement with a semicolon.

apples = 7;

oranges = apples + 1;

"apples = 7" must be done first, then "oranges = apples + 1" will store 7+1 or 8 into oranges

Given x = 22 and y = 99. What are x and y after the given code?

1)

>> x = y;

>> y = x;

x is 99 and y is 22.

x is 22 and y is 99.

x is 99 and y is 99.

x is 99 and y is 99.

>> x = y;

>> y = x;

>> x = y;

x is 99 and y is 22.

x is 99 and y is 99.

x is 22 and y is 22.

x is 99 and y is 99.

>> tempVal = x;

>> x = y;

>> y = x;

x is 99 and y is 22.

x is 99 and y is 99.

x is 99 and y is 99.

>> tempVal = x;

>> x = y;

>> y = tempVal;

x is 99 and y is 22.

x is 99 and y is 99.

x is 99 and y is 22.

numNickels = 5

numDimes = 10

% Write a statement that assigns numCoins with numNickels + numDimes

numCoins = numNickels + numDimes

Given a Fahrenheit value temperatureFahrenheit, write a statement that assigns temperatureCelsius with the equivalent Celsius value. While the equation is C = 5/9 * (F - 32), as an exercise use two statements, the first of which is "fractionalMultiplier = 5/9;".

77 degrees fahrenheit

% Write a statement that assigns fractionalMultiplier with 5/9

% Modify the statement below to convert Fahrenheit to Celsius,

% assigning temperatureCelsius with the Celsius value

temperatureCelsius = (5/9) * (77 - 32) = 25

% Write a statement that assigns myExamScore with 82

myExamScore = 82

% Write a statement that assigns myCurvedExamScore with myExamScore + 5

myCurvedExamScore = myExamScore + 5

Which are valid identifiers?

1) r2d2

2) name$

3) _2a

4) pay_day

5) pay-day

6) 2a

7) y____5

8) switch

1, 4 and 7

The statement "myInt = 44" creates an integer variable.

True

False

false

The statement "myNum = 0.1" creates a single-precision floating-point number because 0.1 is small enough for single precision.

True

False

false

A double-precision number's range is about 10 times greater than a single-precision number's range.

True

False

false

The default MATLAB floating-point representation can represent various numbers from -1.79e+308 to +1.79e+308.

true

The smallest positive number that the default MATLAB floating-point representation can store is 1.1755e-38

True

False

false

Suppress the output of all assignment statements.

1)

Write a statement that assigns the double precision floating-point variable tempKelvin with 0.0.

tempKelvin = 0.0;

Assign celsiusVal with kelvinVal minus 273.15.

celsiusVal = kelvinVal - 273.15;

Using notation similar to 6.02e23 and starting with 3.1, write a statement to assign variable wrenchTorque with the value 3,125.99.

wrenchTorque = 3.12599e3;

Complex numbers.

Assume i and j are the predefined values for the imaginary component of an imaginary number.

1)

What is the result of numA = i * i?

-1

What will the command window display after the assignment numB = 4.5 + 2*i?

numB = 4.5000 + 2.0000i

What will the command window display after the assignment numC = 3.2 + 5*j?

numC = 3.2000 + 5.0000i

Rewrite the following expression without using the * symbol:

numD = 7 + 5*j;

numD = 7+5j;

Rewrite the following expression without using i:

numE = 3 + 6i;

numE = 3 + 6j

Mathematical constants.

Which of the following variables are predefined mathematical constants?

1) Eps

2) J

3) NaN

4) e

5) inf

3

Write a statement that assigns circleArea with the circle's area given circleRadius

circleRadius = 5

% Modify to use built-in math constant pi.

circleArea = picircleRadiuscircleRadius

Evaluating expressions using precedence rules.

Note: This activity omits parentheses to test knowledge of precedence rules. But programmers should use parentheses to make evaluation order explicit.

1)

Does 2 / 2 * 3 equal 2/6?

Incorrect

/ and have equal precedence so are evaluated left to right, thus (2/2)3, which is 1*3, yielding 3.

Does 2 / 3 ^2 equal 4/9?

Incorrect

Exponent has higher precedence, so 2/(3^2) is 2/9.

Does 2 + 3 * 4 - 4 equal 16?

Incorrect

* has higher precedence, so 2 + 12 - 4 is 10.

Does 2 ^ 3 ^ 2 equal 64?

Correct

The power operators evaluate left to right, so (2^3)^2 or 8^2, which is 64.

Does -4 ^ 2 equal -16?

Correct

^ has higher precedence than -, so -(4^2) is -(16).

Precedence rules.

Select the expression whose parentheses enforce the compiler's evaluation order for the original expression. Note: Using such parentheses is preferable over relying on precedence rules.

y + 2 * z

y + (2 * z)

z / 2-x

(z / 2) - x

x y z

(x y) z

x + y ^ 3

x + (y ^ 3)

x + 1 * y / 2

x + ((1 * y) / 2)

x / 2 + y / 2

(x / 2) + (y / 2)

What is totCount after executing the following?

numItems = 5;

totCount = 1 + (2 numItems) 4;

44

After (2 5) is evaluated, 4 is evaluated because * has precedence over +

Multiple statements on a line.

1)

What is val after executing the line num = 6; num = num * 2; val = num + 1;

13

num will assigned with 6 * 2 or 12. Then val will be assigned with 12 + 1 or 13.

What is x after executing the line x = 5; y = 9; y = x; x = y;

5

Write a statement that assigns finalResult with firstSample plus secondSample, divided by 3. Ex: If firstSample is 18 and secondSample is 12, finalResult is 10.

finalResult = (1/3) * (firstSample + secondSample)

A drink costs 2 dollars. A taco costs 3 dollars. Write a statement that assigns totalCost with the total meal cost given the number of drinks and tacos.

Ex: 4 drinks and 6 tacos yields totalCost of 26.

numDrinks = 4 % Number of drinks

numTacos = 6 % Number of tacos

% assigns totalCost with the total meal cost given the number of drinks and tacos

totalCost = (24) + (63)

Expression with multiple exponents: Computing wind chill

Wind chill (C) is computed from the air temperature (T) and wind speed (W): C = 35.7 + 0.6T - 35.7W^0.16 + 0.43TW^0.16

Write a statement that assigns windChill (C) with the wind chill given airTemp (T) and windSpeed (W).

Ex: If airTemp is 32 and windSpeed is 10, then windChill is assigned with 23.1871.

airTemp = 32;

windSpeed = 10;

% Assigns windChill with the temperature felt given airTemp and windSpeed

windChill = 35.7 + 0.6(32) - 35.7(10)^0.16 + 0.43(32)(10)^0.16

Repeated commands.

1)

Variable num is initially 2. The command num = num * 2 is typed and entered once; then the up-arrow key is pressed followed by enter, three times. What is num?

32

num = num 2 is executed four times, leading to 22 or 4, then 42 or 8, then 82 or 16, and finally 16*2 or 32.

What is the next value after 34 in the Fibonacci rabbits example?

55

Characters.

1)

Write a statement that assigns variable delimChar with the comma character. End with a semicolon.

delimChar = ', ';

Given x='a'; y='b', assign x with the current value of y. End with a semicolon.

x = y;

What is the decimal number stored in a char variable delimChar after the following statement: delimChar = 'a';

97

Declaring a character

Write a statement that assigns middleInitial with the character T.

myChar = 'T';

middleInitial = myChar

String scalars and character vectors.

1)

Assign variable unitName with character vector: miles

unitName = 'miles';

Assign variable unitName with string scalar: nautical miles

unitName = 'nautical miles';

Assign variable allowBoat with character vector: OK'ed

allowBoat = 'OK''ed';

Assign variable phrase with string scalar: Isn't it OK?

"Isn't it OK?"

Write a statement that assigns the logical variable isAvailable with the logical value 'true'.

isAvailable = true

Given the following script saved in file CostDrive.m:

miles = 100;

costPerMile = 0.30;

cost = miles * costPerMile;

What is the command line statement to run the script?

CostDrive (with .m omitted)

Assume that no variables have been assigned yet in the workspace. What statement would calculate the speed in miles per hour for a distance of 56.9 miles and elapsed time of 73 minutes?

distanceMiles = 56.9; timeSecs = 73*60; CalculateMPH

Assume that no variables have been assigned yet in the workspace. How many variables would be assigned after executing the following code:

distancePes = 1000; timeSecundae = 55; RomanUnitsToMPH

8

Suppose distanceMiles equals 1870, timeSecs equals 343440, and speedMPH equals 55.0. What is the value of speedMPH after calling CalculateMPH?

19.6

What is the only character that indicates a comment?

%

Type the first line of a function definition for a function named CubeNum with input xVal and output yVal .

function yVal = CubeNum (xVal)

Write a statement that assigns variable myNum with the result of a call to the function defined below with arguments 3 and 9

function o1 = CalcR( i1, i2 )

myNum = CalcR(3, 9)

What happens to input and output variables in a function call?

The following function purposely violates good practice in order to test understanding of the underlying concepts of a function:

function out = PlusOne( inVar )

inVar = inVar + 1;

out = inVar;

end

1)

What is the value of inVar in the global workspace after executing:

inVar = 1;

out1 = PlusOne(inVar);

1

What is the value of inVar in the global workspace after executing:

inVar = 1;

inVar = PlusOne(inVar);

2

Assign y with 5 plus x.

Ex: If x is 2, then y is 7. If x is 19, then y is 24.

function y = IncreaseValue(x)

% x: User defined value that is added to 5

% Modify the line below to y = 5 + x

y = 5 + x;

end

Code to call your function :

IncreaseValue(2)

Function definition: Double down

Complete the DoubleDown function to return twice the initialValue.

function finalValue = DoubleDown( initialValue )

% Complete the function to return twice the initialValue

finalValue = 2*initialValue

end

DoubleDown(5) % Change the input to DoubleDown to test other values