subs command does not create symbolic variable?

I am using MATLAB R2011a. I have symbolic math toolbox installed. When I use the "subs" command to replace a value in a symbolic variable, instead of symbolic variable a normal variable is created ... My code is

>> f=int(g,x)

f =

asin((2*x)/5 - 4/5)/2

>> subs (f,x,3)

ans =

      0.2058

What am missing?

[nafis irtija]

In the mathworks tutorial video they wrote

>>f3=subs(f,x,3)

and the variable f3 was symbolic.when i write the same code,f3 is not symbolic.and they used "eval(f3)" to get the value 0.2058.when I write

eval(f3)

it gives an error.

[John D'Errico]

It is difficult to know, since your version is so old. It works fine for me. For eample, since I do not have g, I did this:

syms x
f = asin((2*x)/5 - 4/5)/2
f =
asin((2*x)/5 - 4/5)/2

subs(f,x,3)
ans =
asin(2/5)/2

with no problems. But I am using the current release.

Answer 1

[Martin Brown]

You've evaluated

asin((2*3)/5 - 4/5)/2

which is indeed 0.2058. It's no longer symbolic?