how to get function value?

Hi I want to evaluate function and its derivative at a=2 , how to do that?

syms a
b=2
e=0.9 
q=1.2
g=2
k=3
d=0.5
f=(q*b*e/a-d*e)/((q^2)*(e^2)/a+2*e*g)
diff(f)

Answer 1

[madhan ravi]

df(a) = diff(f)
df(2)

[Ani Asoyan]

thank you! and what about function ?

[madhan ravi]

The same way

[Ani Asoyan]

I do f(2) but it doesn't work

[madhan ravi]

P.S: You have some troubles with copying.

f(a) = (q*b*e/a-d*e)/((q^2)*(e^2)/a+2*e*g)
f(2)

[Ani Asoyan]

oh I'm so bad at matlab :D .. thank you

Answer 2

[David Hill]

syms a;
b=2;
e=0.9;
q=1.2;
g=2;
k=3;
d=0.5;
f=(q*b*e/a-d*e)/((q^2)*(e^2)/a+2*e*g);
df=diff(f);
fvals=eval(subs(f,1:10));%evaluate f from 1:10 (if you want actual symetric value eleminate the eval function
dfvals=eval(subs(df,1:10));

[Ani Asoyan]

does eval give approximate value or exact value/?

[madhan ravi]

Nah using eval(...) is o]absolutely not needed here! forget it!

[Ani Asoyan]

I agree,, David Hill , thanks for the effort, but I think I'll go with the other answer, sorry