7.16 已知粒子遵从经典玻耳兹曼分布,其能量表达式为-|||-=dfrac (1)(2m)(({p)_(x)}^2+({p)_(y)}^2+({p)_(2)}^2)+a(x)^2+bx-|||-其中a、b是常数,求粒子的平均能量.

dfrac (dy)(dx)=(x)^2+(y)^2 B . dfrac (dy)(dx)=(x)^2+(y)^2 C .dfrac (dy)(dx)=(x)^

证明:函数-|||-f(x,y)= ((x)^2+(y)^2)sin dfrac (1)(sqrt {{x)^2+(y)^2}}, ^2+(y)^2neq 0,

抛物面=dfrac (1)(2)((x)^2+(y)^2) 被平面 =dfrac (1)(2)((x)^2+(y)^2)所截下有限部分的面积是=dfrac (1

.用极坐标计算下列二重积分:-|||-iint sin sqrt ({x)^2+(y)^2}dxdy ,其中 = (x,y)|{m)^2leqslant (x)

已知Σ为锥面=sqrt ({x)^2+(y)^2}在柱体=sqrt ({x)^2+(y)^2}内的部分,则曲面积分=sqrt ({x)^2+(y)^2}

( A ) = (x,y,z)|{x)^2+(y)^2+(z)^2=(a)^2,zgeqslant 0} ( B ) = (x,y,z)|{x)^2+(y)^

求旋转曲面=(x)^2+(y)^2在点=(x)^2+(y)^2处的法线方程A.=(x)^2+(y)^2B.=(x)^2+(y)^2C.=(x)^2+(y)^2D

6 化简表达式(x)^2+(xy-(x)^2)-(5(x)^2+2xy)6化简表达式

一维谐振子的Hamilton算符为-|||-=dfrac (1)(2m)(p)^2+dfrac (1)(2)m(omega )^2(x)^2 (1)-|||-x

设函数 (x,y)=1-dfrac (cos sqrt {{x)^2+(y)^2}}(tan ({x)^2+(y)^2)} ,则当定设函数 (x,y)=1-df