Explore topic-wise InterviewSolutions in .

Correct option is (d) Cannot conclude

For explanation: The use of the line command is primarily seen in plotting the graphs without the HOLD command. But we can put the ARGUMENTS within the plot command itself so that we don’t have to put an EXTRA line of code. This SAVES COMPLEXITY, although we have increased the length of our code.

Right OPTION is (b) Bar PLOT

The EXPLANATION: The data contains 3 parameters- profit, industry, quarter. We can use the histogram plot if the profits are strikingly different but usually it is not so. So, we should use Bar plot to draw 3 BARS for 3 industries showing 3 separate profits over 3 separate quarters.

Correct choice is (a) .\ and ./

Explanation: In MATLAB, if we WANT to perform left division of TWO matrices we NEED to write a.\b while for the right division we have to write a./b. for left division respectively.

Correct choice is (a) matrix LABORATORY

Explanation: MATLAB stands for matrix laboratory which is multi-paradigm numerical COMPUTING environment and fourth-generation PROGRAMMING LANGUAGE.

The CORRECT answer is (c) vpa(solve(‘cos(x)=1/2’))

The explanation is: To find the exact value of non-integer constants, we use the function ‘vpa()’. MATLAB won’t understand SIN(x)=1 as an equation until we initialise x as a symbolic VARIABLE. syms x;eqn = cos(x) == 1/2;vpa( solve(eqn,x)) would’ve generated the same answer but it has 3 LINES while vpa(solve(‘cos(x)=1/2’)) has only 1 line. Once we introduce the variable x as a string, MATLAB understands that it is a symbolic object.

The correct answer is (a) Computational difference

For EXPLANATION: MATLAB follows a precedence of operators while doing any computation. So (9*1-8) is DONE like this: 9*1-8=9-8=9. But (9-1*8) is done like this: 9-1*8=9-8=1. Even though the answers are same, there is a computational difference between evaluation of the TWO expressions in MATLAB.

Correct answer is (a) a=pi;b=’pi’;

The best I can explain: After ENTERING the code in MATLAB, the WORKSPACE VIEW is:

A character VARIABLE is stored by declaring the character value within a pair of single inverted commas. An INTEGER variable is stored by simply declaring the variable with the integer value. pi is stored in MATLAB as an integer value itself of 3.1416.

Correct answer is (b) The PLOT function is not defined with a constant variable RANGE

For explanation: If the student is USING the hold command, the student has to keep the SCALE and range of one axis same. Then he can plot the functions of other dependent variables, which depend on the independent variable range previously defined. If the plot function contains an ENTIRELY different set of arguments, MATLAB will produce an error.

Right answer is (a) no difference

Explanation: Both HOLD on and hold all COMMANDS are used to hold the graph of a FUNCTION. There is no difference between them. To avoid confusion, one can only WRITE hold to hold a graph and again enter the COMMAND hold to release the graph.

Right answer is (a) mtimes(A,N)

To explain: The syntax of the function to multiply a MATRIX with itself n TIMES is ‘mtimes(A,n); where A is the matrix itself and n is the number of times the matrix need to be multiplied to itself. There are no function ntimes() in MATLAB and the rest of the options show incorrect syntax.

Right choice is (c) diary

Easy explanation: The diary function creates a LOG of keyboard input and the resulting TEXT output, with some exceptions. The output of diary is an ASCII file, suitable for searching in, printing, INCLUSION in most reports and other DOCUMENTS.

The CORRECT CHOICE is (a) Nothing special

The best I can explain: a./b is same as b.\a. In the former, we are PERFORMING left division so b is divided by a. In the latter, we are performing right division so b is again divided by a. Thus, it is obligatory that a./b=b.\a. Hence, nothing special can be said about the TWO matrices A and B.

Correct CHOICE is (b) Linear bivariate

Best explanation: The student GETS an angle histogram plot. So, he used the wrong function. But the plot was GENERATED. So, his lines of code have defined the date in terms of ANGLES. PLUS he has used the rose command in place of the pie command.

Correct ANSWER is (a) TRUE

Explanation: If a=[], a is a matrix but not a VECTOR in MATLAB. Hence, the above statement is true.

Correct CHOICE is (c) “ ‘ ”

Explanation: It is pre-defined in MATLAB that if we WANT to find the transpose of a vector, we will have to use the “ ‘ ” symbol following the vector or the vector name. “ ^ ” is used to raise the power of a VARIABLE while “ * ” is used for multiplication purposes. “ ~ ” is used to denote not-equal to the OPERATOR which is “ !~ ”. HENCE option “ ‘ ” is correct.

The correct option is (b) False

Explanation: The uniform distribution can TYPICALLY RANGE from (-Inf,Inf), i.e. the lower and UPPER LIMITS of the distribution cannot be LESS than or -Infinity or more than Infinity respectively. Hence, this leads to an error.

Correct option is (a) 8 bytes and 16 bytes

For EXPLANATION: The SIZE of double variables holding integer constants is 8 bytes. The size of symbolic variables is 112 bytes. These are predefined data type sizes in MATLAB.

Correct option is (c) SIMPLIFY(log(x^20)-log(x^13)–log(x^7),’IgnoreAnalyticConstraints’,TRUE)

The explanation is: Option simplify(log(x^20)-log(x^13)–log(x^7),’IgnoreAnalyticConstraints’,true) would evaluate to 0. The cases are used to produce a GREATER simplified EXPRESSION for a polynomial. simplify(log(x^20)-log(x^13)–log(x^7)) does not give any different output but the expression itself. Option log(x^20) – log(x^13) – log(x^7) is incorrect since the powers should be represented as log(x^20) in MATLAB.

The correct option is (c) clc

Easiest explanation: clc clears all INPUT and output from the COMMAND Window display and provide a “clean screen”. After using clc, you cannot use the SCROLL bar to SEE the history of functions, but you still can use the up ARROW key, ↑, to recall statements from the command history.

The correct option is (d) He is not using the hold function

For explanation I would say: The hold command is used to hold the cursor, DEVELOPED after creating a plot, so that the NEXT GRAPH, when PLOTTED, will appear on the same window where the initial graph was plotted. He may use the line function, but in the code he is using the plot function. So he has to enter the function hold before PLOTTING the graph of z(t).

Right OPTION is (a) plot3

The best I can explain: The function ‘plot3()’ is USED to PLOT a 3d graph. The axes of the system can be mentioned as x,y,z so the plot which will be returned will be for a CUBE if the length cut off from each axis are equal.

Right option is (b) poly([roots as a COLOUMN vector])

The BEST I can explain: To FIND the roots, one has to store the given roots in a 1*n column vector, SAY p, and then extract the co-efficients of the polynomial by typing poly(p). This would return the co-efficients of the polynomial in descending order from left to right.

Right answer is (b) disp(x)

The explanation: disp(X) displays the value of VARIABLE X without printing the variable NAME. ANOTHER way to display a variable is to type its name, but this displays a leading “X =”, which is not always IDEAL. If a variable contains an empty array, disp returns without displaying anything.

Right answer is (d) USE uipanel()

For explanation I WOULD say: The uipanel can be used to give a major title to the SUBPLOTS CREATED. The title name is given as a string input by the following way:

f=figure;

c=uipanel(‘PARENT’,f,’BorderType’,’none’);

c.Title=’Title Name’;

c.TitlePosition=’centertop’

The CORRECT answer is (b) Histogram

For explanation I WOULD SAY: A bar graph is USED to show the contribution of 3 batsmen with one batsman in a partnership. Thus it can be inferred who has CONTRIBUTED highest to the partnership among the three.

Correct option is (a) dbstep

The EXPLANATION is: The function ‘dbstep’ helps in single step execution while ‘dpstepin’ helps to enter into a function. The function ‘dbstatus’ helps to list all the BREAKPOINTS in a function while ‘dbcont’ helps to continue execution. These are the pre-defined debugging commands in MATLAB.

Correct choice is (c) The equation may be solvable but the function ‘solve’ cannot PRODUCE a solution

To elaborate: It may so happen that an equation may not be solvable but DUE to some mistake, the function solve0 has encountered an argument which is an equation whose Left hand side could never be equal to the right hand side. It may ALSO happen that some separate solution is present but the function cannot produce the solutions. We need to CHECK separately for such cases by applying some other methods of solving equations though, generally, this does not happen.

Correct answer is (a) It does not show the values of the VARIABLE

To explain: whos returns the name, size, bytes and class of the variables USED in the current program. To GET the value of any variable, we need to TYPE the variable and press Enter.

The correct choice is (c) syms ‘x’MAKES the declaration long lasting while sym ‘x’ makes the declaration short lasting

The explanation: sym ‘x’ makes the declaration short lasting. If it is ASSIGNED to a VARIABLE, x say, the FUNCTION is EQUIVALENT to syms ‘x’. This makes syms ‘x’ long lasting.

The correct answer is (a) Syntax and runtime

Easiest explanation: Usually, there are two KINDS of errors in any programming language. They are syntactical errors and runtime errors. Syntactical errors arise DUE to the programmer not FOLLOWING language specific syntaxes. Runtime errors RISE due to faulty logic decided for the program, the error is called Runtime error.

Correct answer is (a) quiver()

To explain I WOULD say: The function ‘quiver()’ is a pre-defined function in MATLAB. It is often USED to plot vector fields in MATLAB. The pie3 function is used to plot a 3-d pie plot. The ezplot() generates a 3d plot while the CONTOUR() is used to generate the contour plot of a SPECIFIED MATRIX.

The correct answer is (b) a[] is for empty linear ARRAY while a{} is for empty CELL array

Explanation: To INITIALISE a cell array, named a, we use the SYNTAX ‘a{}’. If we need to initialise a linear array, named a, we use the syntax ‘a[]’. This is pre-defined in MATLAB.

The correct answer is (a) True

Explanation: To declare a scalar, we only need to declare a variable in MATLAB with a constant expression. We don’t need to include the expression with any KIND of brackets. But, we need to put the EXPRESSIONS within a bracket for row or COLUMN vector.

The correct option is (b) DOUBLE Precision

For EXPLANATION I would say: MATLAB stores any integer VARIABLE as a double data type of 64 bits. For single precision, the function is ‘single()’ but if not mentioned, the value will be stored in double precision.

Correct option is (b) False

Best explanation: Any argument within the PARENTHESES of the FUNCTIONS ‘sin()’, ‘cos()’ are taken to be in radians. If the argument is to be processed in DEGREES, the FUNCTION is modified as sind() and COSD().

Correct option is (c) Attributes of variables, script FILES, functions from command window

To elaborate: The WORKSPACE window shows the attributes of variables, script files, functions from the command window for an ongoing PROGRAM. It is more descriptive than the whos function.

The correct option is (a) a = B^T

For explanation: ‘a./b’ means that elements of a are divided b while ‘b./a’ means that the elements of b are divided by a. If the result of the latter is the transpose of the former, it SUGGESTS that a=b^T. This is because element-wise division is performed by the operator ‘./’. So the resultant MATRIX is a direct symbolisation of the nature of occurrence of elements in EITHER matrix. Hence option a=b^T is correct.

Right CHOICE is (a) ABS()

EXPLANATION: In the function sqrt(), we have to write the polynomial which shows the sum of squares of the real and imaginary part within the parentheses. But in abs(), we only have to enter the variable which we’ve used to define the complex NUMBER. So abs() is more preferred.

The correct ANSWER is (d) sqrt(10) returns exact value while sqrt(sym(10)) returns 10^(1/2)

To explain I would say: ‘sqrt()’ is a predefined FUNCTION used to FIND a square root of large numbers to reduce the complexity of equation. sqrt(sym(10)) introduces 10 as a symbolic object to the MATLAB workspace.

Thus it will return 10^(1/2) as a symbolic expression and won’t DIVULGE the exact root. This helps often to reduce an equation before INCREASING program complexity in MATLAB.

The correct ANSWER is (d) polyval(c,a), c is a ROW vector

To elaborate: polyder(p)and polyint(p) produces the differentiation and integration of the polynomial p. Polyval(c,a) is the correct form of the function to evaluate the value of a polynomial whose INDEPENDENT variable is a. The value of a has to be provided FIRST before WRITING the function.