The GATE Grind

GATE 2020 BM – Question 18

Signals and Systems · Laplace and Fourier Transforms · 1 mark · Multiple choice

X(s) is the Laplace transform of x(t). Assuming x(0)=0, find the Laplace transform of dx(t)/dt.

  1. $sX(s)$
  2. $X(s)/s$
  3. $dX(s)/ds$
  4. $(1/s)dX(s)/ds$

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: (A) $sX(s)$

Explanation

The unilateral derivative property is L{x′}=sX(s)−x(0⁻). With zero initial value the subtraction term vanishes, leaving sX(s), A. Differentiation in the transform variable corresponds to multiplication by time rather than differentiation with respect to time.

More Laplace and Fourier Transforms questions

All Laplace and Fourier Transforms questions →