How does 'subs' in MATLAB work with negative large fractional number?

syms x y A A=x^2*y; subs(A,{x y},{4 2e-8})

ans =

3022314549036573/9444732965739290427392 ----- wrong result!!!

syms x y A A=x^2*y; subs(A,{x y},{4 2e8})

ans =

3200000000 ------ correct result!!

How do I resolve this type of problem? Please help.

Answer 1

[Mischa Kim]

Rahul, the first result is correct as well. MATLAB simply outputted the result as a fraction. Use

 double(subs(A,{x y},{4 2e-8}))
 ans =
     3.200000000000000e-07

which is the same as

 3022314549036573/9444732965739290427392
 ans =
     3.200000000000000e-07

[Rahul Bhattacharya]

Thank you, Mischa!!