Find out transfer function in control system

[jaus tail]

Homework Statement

Homework Equations

Using Laplace
TF = C (s) / R (s)

The Attempt at a Solution

Laplacing the equation:
3s C(s) + C(s) = R(s) e^-3s
So C(s) / R(s) = e^-3s / (1 + 3s)
Book answer is B
I know ramp input is At. Do I laplace it as: A/s²?
I'm not sure where I'm wrong

 

[rude man]

The wording is wrong.
The transfer function is in fact 1/(3s+1). A transfer function is output/input and so is not a function of the particular input.
What they might have meant is the Laplace transform of the output, but if r(t-3) is a ramp t delayed by 3 sec. then again none of the proffered answers is correct. It would be e^-3s/{s²(3s+1)} as I think you surmised.

 

[anorlunda]

@jaus tail , you seem to be using textbooks that have many errors. I hope that as you advance, you will get access to better quality teaching materials.

 

[jaus tail]

@jaus tail , you seem to be using textbooks that have many errors. I hope that as you advance, you will get access to better quality teaching materials.

Yeah but exam is very near and I cannot study from another book now. I'll get more confused.
This forums is very helpful.