Question

The laplace transform of step function, u(t), can be calculated by using _____

(a) syms t; laplace(t/t)

(b) laplace(1)

(c) laplace(t/t)

(d) sym t; laplace(t/t)

This question was addressed to me in homework.

Query is from Laplace Transform in portion Control System Applications of MATLAB

Answer 1

The correct answer is (a) syms t; laplace(t/t)

The explanation: The laplace command won’t understand 1 is a unit function. Also, if we don’t define t as symbolic, it won’t be able to understand ‘t/t’. Finally, sym t doesn’t properly define t for using it in the laplace command so we need to write t=sym(‘t’) while using the sym command. Instead of this, we write syms t to define it, as a symbolic variable, for the laplace command.