Difference between D(f)(x) and diff( f(x) , x )

Question

VincentLec 2016-6-23

回答： Muhammad Usman Saleem 2016-6-23

Hello, So, I'm using the symbolic notation and I have defined both x and f(x) as symbolic functions like this

syms x f(x)

After a couple of operations, I get (in my Command window) a formula that includes both D(f)(x) and diff(f(x),x).

D(f)(x)+...+diff(f(x),x)

I was wondering if there is any difference between both of them or if they both represent the derivative of f in respect towards x.

Thanks a bunch

Answer 1

Muhammad Usman Saleem 2016-6-23

let say you are working with two for loops one has index variable f and other is x

the

D(f)(x)

means everytimes these loops run you are calling value of vector(may matrix) with indices f,x

while

diff( f(x) , x )

means you are calling vector f element of index x and with x( suppose your for loop has index variable x) taking its just difference.