MATLAB Answers

how to differentiate a function and then evaluate at a predefined variable?

16 views (last 30 days)
sam plant
sam plant on 6 Nov 2018
Commented: madhan ravi on 6 Nov 2018
If i wanted to differentiate f=x*y with respect to y and then evaluate at a value y = 6 say. how would i do this? i would write the code syms y f=x*y g=diff(f) but then how would i go about the evaluation because it seems y is now fixed as a symbol. Also, i have this as predefined input values x,y so i would like to use the y value predefined as i'm writing it in a function

  0 Comments

Sign in to comment.

Accepted Answer

madhan ravi
madhan ravi on 6 Nov 2018
syms x y
f=x*y
A=diff(f,y)
subs(A,y,6)

  3 Comments

sam plant
sam plant on 6 Nov 2018
Thank you! I used that example to just keep it simple, my actual equation was involving logs and 3 variables but i just wanted t keep the principle the same. It's working after reading this, i appreciate the help!
madhan ravi
madhan ravi on 6 Nov 2018
Anytime :) , I understood that you needed an example to know the functions , Happy Matlab(ing)

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by