Nếu u(t)=v(x) thì: dt = v(x)/u((t) dx

A. $dt=\frac{v\left(x\right)}{u\left(t\right)}dx$

B. $dt=\frac{v\text{'}\left(x\right)}{u\text{'}\left(t\right)}dx$

C. $dx=\frac{v\left(x\right)}{u\left(t\right)}dt$

D. $dx=\frac{v\text{'}\left(x\right)}{u\text{'}\left(t\right)}dt$