GATE 2023 IN – Question 28
Let $x[n]=u[-n+5]-u[n+3]$, where $u[n]=1$ for $n\ge0$ and zero for $n<0$. The smallest $n$ for which $x[n]=0$ is ______.
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Correct answer: -3 to -3
Explanation
The first step is 1 for $n\le5$; the second is 1 for $n\ge-3$. Their difference is zero throughout $-3\le n\le5$, first at **−3**. The $n\ge0$ in the source defines the unit step; it does not restrict the signal’s domain.