{ x = e–3t, { y = e8t.
y`x=y`t/x`t y`t=(e8t)`=(e8t)·(8t)`=8e8t xt`=(e–3t)`=e–3t·(–3t)`=–3·e–3t yx`=8e8t/(–3·e–3t)=(–8/3)e11t