# Definition of step function

**Unit step function **

**Options: **

a) exists only for positive side

b) is zero for negative side

c) discontinuous at time t=0

d) all of the above

Correct Answer: d) all of the above

**Explanation:**

Unit step function is a type of function that exists only for positive side and is zero for negative side. The unit step function is discontinuous at time t=0.

The unit step function u(t) is defined as

u(t) = 0 for t<0

= 1 for t>0