Replacing symbolic subexpression with unspecified arguments

Hello,

I would like to do a symbolic computation where I have to replace a subexpression with another.

However I can not use the subs instruction, since the parameters are changing:

syms a1 a2 a3 a4 x1 x2 x3 x4 y
y = sin(a1 * sin(x1))
%%Could be any ai and xi

Is there a way to replace the outer sin() with another symbolic function regardless of the parameters?

I'd assume that matlab uses an internal expression tree, but I don't think it's accessible.

Answer 1

[Walter Roberson]

syms a1 a2 a3 a4 x1 x2 x3 x4 y
y = sin(a1 * sin(x1))

y = 

cos(children(y, 1))

ans = 

Answer 2

[Paul]

Not 100% clear on the question. Maybe this?

syms a1 a2 a3 a4 x1 x2 x3 x4
syms a x
y(a,x) = sin(a * sin(x))

y(a, x) = 

y(a2,x2)

ans = 

Answer 3

[Roman Frels]

Thank you for the answers!

Best regards