【判断题】有限差分法的基本思想是在偏微分方程中将偏微商用差商近似代替,得到差分方程。差分方程中未知数是有限的,可通过解差分方程得到微分方程的近似解。
【单选题】函数yx=A2x+8是下面某一差分方程的通解,这个方程是[ ].
【判断题】幼儿皮肤薄嫩,偏于酸性,保护功能差,易受损伤和感染。( )
【单选题】听力原文:Have you heard about an old book of the 19th century which sold for 300 thousand Euros last week? (A) I usually buy paperbacks rather than hardback ones. (B) It is really a best-selling one. (C) ...
【单选题】There is _______desk in the room. _______old book is on it.
【单选题】xt0506717在气相色谱法中,可用作定量的参数是()