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设z=[sin(2π/3)+icos(2π/3)]2,i是虚数单位,则argz等于 () A.π/3B.2π/3D.4π/3 D.5π
设z=[sin(2π/3)+icos(2π/3)]2,i是虚数单位,则argz等于 ()
A.π/3
B.2π/3
D.4π/3
D.5π/3
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设z=[sin(2π/3)+icos(2π/3)]2,i是虚数单位,则argz等于 ()
A.π/3
B.2π/3
D.4π/3
D.5π/3
将下列各复数写成三角表示式:
(1)-3+2i;
(2)sinα+icosα;
(3)-sin-icos
.
求下列各函数的一阶偏导数.
(1)z=exy; (2)z=x+y
(3)u=z2ln(x2+y2); (4)z=(1+xy)y;
(5)z=x2+y2(6)u=sin(x2+y2+z2);
试证: (1)sin(iz)=isinh z;(2)cos(iz)=cosh z; (3)sinh(iz)=isin z: (4)cosh(iz)=cos z; (5)tan(iz)=itanh z; (6)tanh(iz)=itan z
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设el=(cosθ,sinθ),求函数f(x,y)=x2-xy+y2在点(1,1)沿方向l的方向导数,并分别确定角θ.使这导数有(1)最大值,(2)最小值,(3)等于0.
计算第一型面积分:(S)为圆锥面的一部分:x=rcosψsinα,y=rsinψsinα,z=rcosα(0≤r≤α,0≤ψ≤2π),α为常数