Question

If \( x(t) \) is a causal signal, then for \( t < 0 \):

• A. \( x(t) < 0 \)
• B. \( x(t) \) is not equal to zero
• C. \( 0 < x(t) < 0 \)
• D. \( x(t) = 0 \)

Hint:

A causal signal is zero for all negative values of time (\( t < 0 \)).

Answer 1

The Correct Option is D

A causal signal is one that is defined only for \( t \geq 0 \), meaning it is zero for all \( t < 0 \). Therefore, for a causal signal \( x(t) \), we have: \[ x(t) = 0 \quad \text{for} \quad t < 0 \] Thus, the correct answer is \( x(t) = 0 \) for \( t < 0 \).