In the "solve" expression below, I am puzzled why the Maple solution has the natural log argument

((Voh-Vthl) / (Voh-Vtlh)

rather than

((Vthl-Voh) / (Vtlh-Voh)

as I would have expected;

solve(Vthl = Voh + (Vtlh - Voh) * exp-(t / t1), t)

?

Thank you