Clear Filters
Clear Filters

How to change a Function by a Variable

9 views (last 30 days)
How can I change a MATLAB function with a variable? (They are symbolic equations.)
Assume that I have an equation of "A*sin(phi)+B*cos(phi)". I want to replace "sin(phi)" by "2*x/(1+x^2)" , and "cos(phi)" should by replaced by "2*x/(1+x^2)" ? (Notice that x=tan (phi/2) , therefore sin(phi)=2*x/(1+x^2), and cos(phi)=2*x/(1+x^2) ) .
The final symboic equation should look :
"A*2*x/(1+x^2) + B*2*x/(1+x^2)"
syms A B phi x
% ??? Some unknown operations ???
equation_new=A*2*x/(1+x^2) + B*2*x/(1+x^2)

Accepted Answer

Mischa Kim
Mischa Kim on 10 Jan 2021
Edited: Mischa Kim on 10 Jan 2021
Ercan, here you go, for the first term:
syms phi x A B
eq = A*sin(phi) + B*cos(phi)
eq = subs(eq,sin(phi),2*x/(1+x^2))
  1 Comment
ercan duzgun
ercan duzgun on 10 Jan 2021
Dear Mischa Kim,
Thank you very much. It works. I wasn't aware of this command. Thank you.

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!