Question

If f(t) = coshat, its Laplace transform is given by?

(a) s ⁄ s^2-a^2

(b) s+a ⁄ s-a

(c) Indeterminate

(d) (sinh(at))^2

I had been asked this question in an internship interview.

This interesting question is from Existence and Laplace Transform of Elementary Functions topic in chapter Laplace Transform of Engineering Mathematics

Answer 1

Correct choice is (a) s ⁄ s^2-a^2

Easy explanation: The Laplace transform of a function is given by

\(\{f(t)\}=F(s)=\int_0^{\infty} f(t)e^{-st}dt\)

put f(t) = coshat

On solving, s ⁄ s^2-a^2 is obtained.