How do i perform differentiation over summation?

[mahmud_dbm]

 

[Stephen Tashi]

It isn't clear what you mean by $\frac{d}{dx} y$. Are you differentiating a vector $y$ with respect to to another vector $x$ ? (If so, how do you define that sort of derivative?) Or are you differentiating a vector of functions of the scalar variable $x$ with respect to $x$ ?

You say that $x$ has exactly N samples. If $x$ is vector of constants, I don't what you would mean by differentiating with respect to $x$. If you have some function $f(x)$ and some set of constants $c_1,c_2,...$ you can talk about forming the derivatives $f'(c_1), f'(c_2),...$.

 

[mahmud_dbm]

Thank you so much for your reply,
You are right, here x is a vector and H is a matrix, and i want to differentiate Hx with respect to x

Here's the complete problem

that's how far i have gone, probably it's wrong.

 

[mahmud_dbm]

It isn't clear what you mean by $\frac{d}{dx} y$. Are you differentiating a vector $y$ with respect to to another vector $x$ ? (If so, how do you define that sort of derivative?) Or are you differentiating a vector of functions of the scalar variable $x$ with respect to $x$ ?

You say that $x$ has exactly N samples. If $x$ is vector of constants, I don't what you would mean by differentiating with respect to $x$. If you have some function $f(x)$ and some set of constants $c_1,c_2,...$ you can talk about forming the derivatives $f'(c_1), f'(c_2),...$.

please let me know if it's okay!
that's how far i have gone, probably it's wrong.

 

[vela]

Thank you so much for your reply,
You are right, here x is a vector and H is a matrix, and i want to differentiate Hx with respect to x.

You still haven't explained what $x$ is.