- #1

nhoratiu

- 3

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I have a problem with one of the questions given to us in the signals and systems course. If anyone could help me I would greatly appreciate it!

## Homework Statement

integral(from -infinity to +infinity) of u

_{0}(t) * cos(t) dt

u(t) is a step function.

## Homework Equations

Why is this equal to 1 and not to sin(t), for t>0 ?

## The Attempt at a Solution

I thought this is equal to sin(t) but the answer manual says it's equal to 1 because the whole thing transforms into a delta function. How does it do that?