![](https://static.youtibao.com/asksite/comm/h5/images/m_q_title.png)
对下列函数u,求dnu==f(s,t,r),其中s=a1x+b1y+c1z,t=a2x+b2y+c2z,r=a3x+b3y+c3z
对下列函数u,求dnu==f(s,t,r),其中s=a1x+b1y+c1z,t=a2x+b2y+c2z,r=a3x+b3y+c3z
![](https://static.youtibao.com/asksite/comm/h5/images/solist_ts.png)
对下列函数u,求dnu==f(s,t,r),其中s=a1x+b1y+c1z,t=a2x+b2y+c2z,r=a3x+b3y+c3z
A.(H,T)
B.(H,S)
C.(H,R)
D.C
设u(x,t)是初边值问题
的解.求所有使得对任意初始函数φ∈C([0,1]),φ(0)=φ(1)=0成立
设u(x1,x2,t)是中柯西问题
的解,其中在
a) 对哪些(x1,x2,t),函数u(x1,x2,t)等于零?
b) 在的情形下,求
Choose the BEST TERM to match the definition and translate the selected term into Clunese.
A) Ablation L) Nanocomposites
B) Adhesion M) Nettingindex
C) Cohesion N) Plasticizers
D) Degree ofcrystallinity O) Polymer
E) Dielectric constant P) Polymerization
F) Dielectric strength Q) Sealants
G) Fiberloading R) Semi-crystalline
H) Flameretardants S) Specific strength
I) Glass-transitiontemperature T) Viscoelasticity
J) Hysteresis U) Vulcanization
K) Monomers V) Whisker
求下列函数的导数: (1)
(a>0); (2)y=ef(x).f(ex); (3)
(4)设f(t)具有二阶导数,
求f(f,(x)),f(f(x))).
已知A=(x2+3y2z)i+6xyzj+Rk,其中函数R适合
=0,且当x=y=0时R=0.求尺使矢量场A存在函数u满足A=grad u,求出u来,并说明A不是管形场.