I applied online on the Mathworks website and received a call from HR a few days later. The initial questions were the basic five questions already posted on Glassdoor.

The next round was an hour-long technical phone interview. Tip: Study all the questions mentioned on Glassdoor, as approximately 95% of them are repeated. You will likely be called for the next round only if you answer 85%-90% of these questions correctly. This applies to intern interviews as well, as this technical round remains the same. The questions are often asked in a rapid-fire format, so be well-prepared and answer them concisely. Here are the questions asked to me:

MATHS

• What is an invertible matrix?
• Given a 3x3 matrix, is it invertible? (Check determinant=0 condition)
• Given a 2x2 matrix, find the eigenvalues.
• What is the rank of a matrix?
• Given a 3x3 matrix, find its rank.
• Given two vectors, find a third vector perpendicular to both. (Take the cross product)
• Given velocity v=2+3(t^2), find acceleration and position at t=4, with initial velocity=0 at t=0.
• Is the integral from -Infinity to +Infinity a definite integral or an indefinite integral?
• Find the limit x→0 of sin(x)/x. Discuss L'Hôpital's rule.

BASIC PROGRAMMING

• What is OOP?
• What is polymorphism?
• Find duplicate elements in an array.
• How do you execute a .exe file in the Windows command prompt?
• What is a recursive function?
• How do you check where a program (in any language) is taking more time to execute and how would you optimize it? (This was a vague question).

C LANGUAGE

• What does #include mean?
• Difference between <stdio.h> and "stdio.h".
• Discuss pass-by-value versus pass-by-reference when passing a character array.
• Difference between && and &.
• Inline functions: When to use and when not to use them?
• int a = 5; float b = 5/2; Is b equal to 2 or 2.5? Why?
• Provide a one-line C code to identify whether a number is odd or even, apart from using the number % 2 == 0 method.
• Difference between struct and union.

MATLAB

• Meaning of A.^2 and A^2 for matrix A.
• When do you use % and when do you use ! in MATLAB?
• What does @ mean in MATLAB?
• Errors while executing an m-file, e.g., function not present or incompatible data arguments. Why are they encountered? How to fix them?
• Extract every 3rd element in an array of 100 elements.
• Provide the syntax to plot (1,11), (2,22), (3,33) on the same plot, also adding green color and '*' markers.
• How to add xlabel and ylabel to a graph?
• How to add a path?
• If you have variables a, b, c in the workspace, how do you delete only b?

SIGNAL PROCESSING

• Nyquist criterion.
• IIR versus FIR.
• Given an impulse to a linear discrete system with h[n] = [1 2 3 5 10] and an input signal frequency of 100Hz, what is the output frequency?
• Why does a bicycle wheel appear to be rotating backward when the bicycle is actually moving forward?
• Difference between Continuous Time Fourier Transform and DTFT.
• Location of poles in relation to the unit circle (inside or outside). Discuss stability.
• Is y[n] = x[n^3] time invariant?
• What is a random process? What is autocorrelation?
• Given h[n] = [4, 0, 1, 0, 2] with the starting point indicated on the second element (arrow on second element), find the Z-transform.
• What is the spectrum of x[n] multiplied by y[n] where x[n] = 5n and y[n] = delta(n-4)?

How do you check where a program (in any language) is taking more time to execute, and how would you optimize it? This was a vague question.

An impulse is applied to a linear discrete system with the impulse response h[n] = [1 2 3 5 10]. The input signal frequency is 100Hz. What is the output frequency?