How do you integrate and differentiate a function with steps and impulses?

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The discussion focuses on integrating and differentiating functions defined piecewise, specifically using cases A and B. Participants clarify that operating on the variable x means applying the operations to both cases separately. There is confusion regarding the notation, particularly whether the same variable x is used consistently across different contexts. A participant points out a potential error in the differentiation of the Heaviside function, highlighting that the derivative should yield the Dirac delta function, which contradicts the earlier interpretation. The conversation emphasizes the importance of clear notation and understanding when dealing with piecewise functions in calculus.
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Given
x = \left\{\begin{matrix} y \;\;\; case\;A\\ z \;\;\; case\;B\\ \end{matrix}\right.
So, operate x means to operate the 2 cases of right side? For example:
\int x\;dx = \left\{\begin{matrix} \int y\;dx \;\;\; case\;A\\ \int z\;dx \;\;\; case\;B\\ \end{matrix}\right.
Correct?
 
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Sure.
 
I don't known that it's operable. It's cool, will be very important to me in engineering!
 
Could you give a concrete example?
 
Jhenrique said:
Given
x = \left\{\begin{matrix} y \;\;\; case\;A\\ z \;\;\; case\;B\\ \end{matrix}\right.
So, operate x means to operate the 2 cases of right side? For example:
\int x\;dx = \left\{\begin{matrix} \int y\;dx \;\;\; case\;A\\ \int z\;dx \;\;\; case\;B\\ \end{matrix}\right.
Correct?
Are you intending for the ##x## in your ##\mathrm{d}x## to be different?
 
x, y and z are only a representative symbol...
 
Jhenrique said:
x, y and z are only a representative symbol...

The problem is that you're using x in two different places, and it's not clear whether or not you intend them to mean the same thing.
 
Jhenrique said:
Given
x = \left\{\begin{matrix} y \;\;\; case\;A\\ z \;\;\; case\;B\\ \end{matrix}\right.
So, operate x means to operate the 2 cases of right side? For example:
\int x\;dx = \left\{\begin{matrix} \int y\;dx \;\;\; case\;A\\ \int z\;dx \;\;\; case\;B\\ \end{matrix}\right.
Correct?


x = \left\{\begin{matrix} y \;\;\; case\;A\\ z \;\;\; case\;B\\ \end{matrix}\right.

\int x\;dx = \left\{\begin{matrix} \int y\;dy \;\;\; case\;A\\ \int z\;dz\;\;\; case\;B\\ \end{matrix}\right.

Is this what you mean?
 
Student100 said:
x = \left\{\begin{matrix} y \;\;\; case\;A\\ z \;\;\; case\;B\\ \end{matrix}\right.

\int x\;dx = \left\{\begin{matrix} \int y\;dy \;\;\; case\;A\\ \int z\;dz\;\;\; case\;B\\ \end{matrix}\right.

Is this what you mean?
Jhenrique said:
operate x means to operate the 2 cases of right side?

I'm trying find... I think that it's math isn't correct, because:
H(x) = \left\{\begin{matrix} 0\;\;\; x<0\\ 1\;\;\; x=0\\ 1\;\;\; x>0\\ \end{matrix}\right.
\frac{\mathrm{d} }{\mathrm{d} x}H(x) = \left\{\begin{matrix} \frac{\mathrm{d} }{\mathrm{d} x}0\;\;\; x<0\\ \frac{\mathrm{d} }{\mathrm{d} x}1\;\;\; x=0\\ \frac{\mathrm{d} }{\mathrm{d} x}1\;\;\; x>0\\ \end{matrix}\right. = \left\{\begin{matrix} 0\;\;\; x<0\\ 0\;\;\; x=0\\ 0\;\;\; x>0\\ \end{matrix}\right.

is wrong, 'cause contradicts the identity d/dx H(x) = δ(x). So, this "technic" above is not useful, although it seems make sense, theoretically... In other words, I'm trying know how do to integrate and derivative, graphically and algebraically, a function with steps and impulses.
 

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