例句與造句

1. Then . with the help of some good results of differential equations theory , some sufficient conditions for all solutions of the equations to be oscillatory are obtained . the way is to proof by contradiction and construct sequence
   1 )的振動(dòng)性，首先，利用積分變換，給出了幾個(gè)引理，將此類差分方程轉(zhuǎn)化為相應(yīng)的微分方程或微分不等式，得出了新變量的一些重要性質(zhì)；然后用反證法和構(gòu)造序列的方法，充分利用微分方程理論中的一些重要結(jié)論，得到此類差分方程解振動(dòng)的若干充分條件
2. It's difficult to find proof by contradiction in a sentence. 用proof by contradiction造句挺難的