Chemical Kinetics

Dada first see whether my approach is correct or not......
-d[A]/dt=k[A] (As the reaction is first order w.r.t A and B is present in excess)
Given,the initial concentration of A is 0.1M.Let the final concentration be xM.
A.T.P
∫d[A]/[A]=-∫k.dt (Integration limit for [A] is from 0.1 to x and integration limit for time is from 0 to 100 secs)
After integrating we get,
log[x]-log(0.1)=-5*10^-1
[x]=10^-3/2........whether this is correct????