∫(v0→v)m/(g+kv)·dv=t∴m/k·∫(v0→v)1/(g+kv)·d(g+kv)=t∴m/k·ln(g+kv) |(v0→v) =t∴ln(g+kv)-ln(g+kv0)=kt/m∴(g+kv)/(g+kv0)=e^(kt/m)∴v=1/k·[(g+kv0)·e^(kt/m)-g]