复变函数视频Lni是多少

i^i是多少?这道题是有答案的,是实数!请高手解答!!!赏100分!
令i^i=a则两边取自然对数ln(i^i)=lnalna=ilni而由复变函数lni=ln|i|+πi/2=πi/2,所以lna=i*πi/2=-π/2,所以a=e^(-π/2),即i^i=e^(-π/2).
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复变函数平时分占多少啊
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为兴趣而生,贴吧更懂你。或第一章复数1i2=-1实部Rezi??1欧拉公式虚部z=x+iyImz2运算①z1?z2?Rez1?Rez2Imz1?Imz2②?z1?z2??Re?z1?z2??Im?z1?z2???Rez1?Rez2???Imz1?Imz2?z1?z2③??x1?iy1??x2?iy2??x1x2?ix1y2?ix2y1?y1y2??x1x2?y1y2??i?x1y2?x2y1?④?x?iy1??x2?iy2?x1x2?y1y2y1x2?x1y2z1z1z2??1??ix2?iy2x2?iy2x2?y2x2?y2共轭复数共轭技巧⑤z?x?iyz???x?iy??x?iy??x2?y2运算律P1页3代数,几何表示z?x?iyz与平面点?x,y?一一对应,与向量一一对应辐角当z≠0时,向量z和x轴正向之间的夹角θ,记作θ=Argz=?0?2k?k=±1±2±3…把位于-π<?0≤π的?0叫做Argz辐角主值记作?0=argz04如何寻找argz例:z=1-iz=iz=1+iz=-1??4?2?4π5极坐标:x?rcos?,y?rsin?i?z?x?iy?r?cos??isin??利用欧拉公式e?cos??isin?可得到z?rei?z1?z2?r1ei?1?r2ei?2?r1r2ei?1?ei?2?r1r2ei??1??2?6高次幂及n次方zn?z?z?z??????z?rnein??rn?cosn??isinn??凡是满足方程??z的ω值称为z的n次方根,记作n??z?r??n1nz?rei???2k????n即r??n??2k??n???2k?第二章解析函数1极限2函数极限复变函数对于任一Z?D都有W??与其对应??f?z?注:与实际情况相比,定义域,值域变化例f?z??zz?z0②limf?z???z?z0称f?z?当z?z0时以A为极限☆当??f?z0?时,连续例1证明f?z??在每一点都连续证:f?z??f?z0?z?z0?z?z0?0所以f?z??在每一点都连续z?z03导数f??z0??limz?z0f?z??f?z0?df?z??z?z0zz?z0时有例2f?z??C?C?'?0证:对?z有lim?z?0f?z??z??f?z?C?C?lim?0?z?0?z?z所以?C??0'例3证明f?z??不可导解:令??z?z0f?z??f?z0?z?z0z?z0?x?iy????z?z0z?z0z?z0?x?iy当??0时,不存在,所以不可导。定理:f?z??u?x,y??iv?x,y?在z?x?iy处可导?u,v在?x,y?处可微,且满足C-R条件?u?v??x?y?u?v?u?v且f??z?????i?y?x?x?x例4证明f?z??不可导解:f?z???x?iy其中u?x,y??xv?x,y???yu,v关于x,y可微所以在每一点都不可导?u?v?1???1?x?y例5不满足C-R条件f?z??Rezu?x,y??xv?x,y??0所以在每一点都不可导解:f?z??Rez?x?u?v?1??0?x?y例6:不满足C-R条件2f?z??z2解:f?z??z?x2?y2其中u?x,y??x?y22v?x,y??0根据C-R条件可得2x?0,2y?0?x?0,y?0所以该函数在z?0处可导4解析若f?z?在z0的一个邻域内都可导,此时称f?z?在z0处解析。用C-R条件必须明确u,v四则运算?f?g??f??g???f?g?z?????f??g??g??z??kf???kf??f?g???f??g?f?g??z???nznn?1☆e????ezz?f?f??g?f?g???g???g2??例:证明f?z??ezz?e???ezxz解:f?z??e?ecosy?iesinyx则u?x,y??ecosyxv?x,y??exsiny?u?v?excosy??excosy?x?y?u?v??exsiny????exsiny?y?x所以e处处解析z任一点z?x?iy处满足C-R条件f??z???u?v?i?excosy?iexsiny?ez?x?x练习:求下列函数的导数f?z??z?z2解:f?z??z?z?x?y22?2??x?iy??x3?ix2y?xy2?iy3?x3?xy2?ix2y?y3?u?3x2?y2?x?v?x2?3y2?y??u?x,y??x3?xy2?u?2xy?yv?x,y??x2y?y3所以?v??2xy?x?根据C-R方程可得?u?v?3x2?y2??x2?3y2?x?y?u?v?2xy????2xy?y?x?x?0,y?0所以当z?0时f?z?存在导数且导数为0,其它点不存在导数。初等函数Ⅰ常数Ⅱ指数函数ez?ex?cosy?isiny?①定义域②e1?ezz2?ez1?z2③ez?2?i?ez?cos2??isin2???ez④ez????ezⅢ对数函数称满足z?e?的?叫做z的对数函数,记作??lnz分类:类比z的求法(经验)目标:寻找可用:z?e???arg?幅角主值z?rei???u?iv?r?eu,ei??eiv过程:z?rei??e??eu?iv?eu?eiv?rei?k?0,?1,?2???????u?lnr,v???2k?所以??u?iv?lnr?i???2k???lnr?i?rgz?lnz?i?argz?2k??k?0,?1,?2??????例:求Ln??1?Ln?1?i?Ln?i?的值arg??1???Ln??1??ln??i?arg??1??2k???i??2k?1?k?0,?1,?2??????arg?1?i???41???ln2?i??2k??k?0,?1,?2??????2?4?Ln?1?i??ln?i?i?arg?1?i??2k???arg?i???2k?0,?1,?2?????????Ln?i??lni?i?argi?2k???1?i??2k???2?Ⅳ幂函数对于任意复数?,当z?0时??z??e?Lnz例1:求i解1?i的值:i1?i?elni1?i?e?1?i?Lni?e?1?i??lni?iArg?i???e???1?i?i???2k???2??e???i?1????2k???2?k?0,?1,?2??????例2:求?1?i?3?i?eln?1?i?3?i?e?3?i?ln?1?i??e1????3?i???ln2?i???2k???????2?4??Ⅴ三角函数?eiy?cosy?isiny??iy?e?cosy?isiny??eiycosy????iye?siny????e?iy2?e?iy2i定义:对于任意复数z?x?iy,由关系式可得z的余弦函数和正弦函数eiz?e?izcosz?2例:求sin?1?i?解:sin?1?i??eiz?e?izsinz?2icos?5?i?1i?1?i??i?1?i?e?e2i1cos?5?i??ei?5?i??e?i?5?i?2????第三章复变函数的积分1复积分定理3.1设C是复平面上的逐段光滑曲线f?z??u?x,y??iv?x,y?在C上连续,则f?z??u?x,y??iv?x,y?CC在C上可积,且有?f?z?dz??u?x,y?dx?v?x,y?dy?i?u?x,y?dy?v?x,y?dxC注:①C是线②方式跟一元一样方法一:思路:复数→实化把函数f?z??u?iv与微分dz?dx?idy相乘,可得?f?z?dz??u?x,y?dx?v?x,y?dy?i?u?x,y?dy?v?x,y?dxCCC方法二:参数方程法C:z?t??☆核心:把C参数??t???f?z?dz???z?t?z??t?dtC例:求?C12①C:0→1?i的直线段②0???1;1???1?iCC解:①C:z?t??t?it10?t?11????t?it??t?it?dt??t?1?i??1?i?dt?1C00?②C1:z?t??t0?t?1C2:z?t??1?it10?t?11???????tdt???1?it?dt?CC1C2001?1????i??1?i2?2?★结果不一样2柯西积分定理例:?z?aC1n?2?idz???0z?a??ei?2?n?1n?1C:以a为圆心,ρ为半径的圆,方向:逆时针解:C:z?x?iy2?0???2??z?aC1ndz??e?1?n?i?0??e?dz??i?n10?ei?n??iei?d??i?n?1?2?02?i?n?1?12??1?n?i?d???ed??1?n?i???0n?1?0?1?ni?☆积分与路径无关:①单联通②处处解析例:求??2zC2??sin???x?a??8z?1dz,其中C是连接O到点?0,2?a?的摆线:?1?cos???y?a??解:已知,直线段L与C构成一条闭曲线。因f?z??2z?8z?1在全平面上解析,2??2z?8z?1?dz?0即??2z?8z?1?dz???2z则2C??L2CL2?8z?1dz?把函数沿曲线C的积分化为沿着直线段L上的积分。由于??2zL2?8z?1dz??2?2?a0?2x2?8??8x?1dx?2?a??2a2?8?a?1??3??故??2zC?8??8z?1dz?2?a??2a2?8?a?1??3??★关键:①恰当参数②合适准确带入z3不定积分定义3.2设函数f?z?在区域D内连续,若D内的一个函数??z?满足条件???z??f?z?z?D定理3.7例:解:若可用上式,则?f?z?dz???z????z?z00zz,z0?D计算?edz0i0iz?i0ezdz?ez?ei?12练习:计算解:?2?i22ze3z?1dz12?i3z2??14i?12edz?ed3z?1?2?26?22?2?i2ze3z?1dz?????4柯西积分公式定理处处解析f?z?在简单闭曲线C所围成的区域内则f?a??1f?z?dz2?i?Cz?aez?1例1:dzz?1zez?1ez?1解:dz?dz?ez?1z?1z?1z?0z??z?0?0sinzz?2z2?1dzsinz1sinz1sinz解:dz?dz??2?isin1z?2z2?1z?2z?22z?12z?1例2:例3:9?zz?7dzz?22z解:z?2z2zzdz?dz?2?iz?2z??i9?z2z?79?z2z??i??5f?z??1f???d??C2?i??zz?D注:①C:z?D②1??z一次分式③找到f?z?f?z?在D内处处解析例4:解sinz?zz?22zz?1dz:sinz?zz?22zz?1dzsinz?zsinz?z?sinz?z?dz?dz?2?i??z1sinz?z???i?sin1?1?z0?z?2z?1z?2z?0?2?2??5解析函数的高阶导数公式:f?n??z??n!f???2?i?C??zn?1d?z?Dn=1,2……应用要点:①z?D②1??zn?1?"n"③精准分离f?????zn?1sinzZ?12z3sinz例:?z?1z?02?1dz?2?i?sinz?2!??2??z?0?06调和函数若g?x,y?满足?g??2g?x2??2g?y2?0则称g?x,y?叫做D内的调和函数若f?z??u?x,y??iv?x,y?在D内解析?2u?2u?2所以v?2?x2??y2??x?y?v?x?y?0把u,v称为共轭调和函数第四章1复数到?zn?n?1?级数理论距离d?z,???z??谈极限此时zn?若有z0?D使得对?d?zn,z0??zn?z0?0n???n???z0为?zn?的极限点记作z0?limzn或zn?z0?n???推广:对一个度量空间?x,d?都可谈极限2极限的性质zn?z0?n??0?n?????zn??n?z0??0???zn??n?z0??0?znz0???n?0??n????n?03zn?xn?iyn?z0?x0?iy0?n????xn?x0???yn?y0?n???4?zn?级数问题Sn?z1?z2?z3???????zn若limSn?S0?n???Sn?部分和数列zn?收敛,反之则发散。则??zn?1?n性质:1若?zn??n都收敛,则??z?????????znnn??n?收敛2若一个收敛,一个发散,可推出发散3??Sn?S0?Sn?1?S0?n????n???若若?a?an?????an???但绝对收敛nn?a收敛,为条件收敛z1?zn等比级数:Sn?z?z?????z?1?z2n??Sn?z1?z?z?1时收敛,其他发散?n???幂级数?Cn?z?z0?n?0?n??z?z0则?C?nn?0n求收敛域?limn??Cn?1Cn?0????????0?????0?????0????1??R?????0???zn例:求?的收敛半径及收敛圆n?1n解:因为limCn?1n?lim?1所以级数的收敛半径为R=1,收敛圆为z?1n??Cn??n?1n泰勒级数泰勒定理:设函数f?z?在圆K:z?z0?R内解析,则f?z?在K内可以展成幂级数f?z???Cn?z?z0?n?0z?nf?n??z0?其中,Cn?,(n=0,1,2……),且展式还是唯一的。n!例1:求f?z??e在z?0处的泰勒展式解:f?z??e在全平面上解析,fz?n??z??ez,f?n??0??1所以在z?0处的泰勒展式为z2zne?1?z??????????2!n!zz???例2:将函数f?z??解11?z2展成z?i的幂级数:f?z??11?z2????111???????????1?i2?1?z??1?i?z?i?n?1???z?i??z?i???????n???????1?2??1?i??1?i?????z?i?2?罗朗级数罗朗定理若函数f?z?在圆环D:r?z?z0?R?0?r?R???内解析,则当z?D时,有f?z??n????C?z?z?n0?n其中Cn?1f???d?n?1??2?i??z01?n?0,?1,?2????例:将函数f?z??内展成罗朗级数。z?1z?2在圆环(1)1?z?2(2)2?z???解:(1)在1?z?2内,由于1z?1,?1,所以z2f?z??1z?1z?2n?111111?????z?2z?12z1?1?2zn??1??z?1??1?zn1???????????n?1??n?12n?0?2?zn?0?z?n?02n?0z(2)在2?z???内,由于12?1,?1,所以zzf?z??1z?1z?2n?n111111?????21z?2z?12z1?1?zz?1??2?1??1?2n?1?1?????????zn?0?z?zn?0?z?znn?1孤立奇点定义:若函数f?z?在z0的去心邻域0?z?z0?R?0?R????内解析,在z0点不解析,则称z0为f?z?的孤立奇点。sinzz2z4z2nn例:?1?????????1?????2n?1!z3!5!sinz1zz2n?3n?1?????????1?????22n?1!z3!zsinz?0为可去奇点z?0为一级极点??????????1????32n?12n?1!zzz3!zz?0为本性奇点第5章留数理论(残数)定义:设函数f?z?以有限项点z0为孤立奇点,即f?z?在z0的去心邻域0?z?z0?R内解析,则称积分记作:Res?f?z?,z0??其中,C:z?z0?例1:求函数f?z??41f?z?dz的值为函数f?z?在点z0处的留数2?i?C1f?z?dz2?i?C??R,C的方向是逆时针。sinz在z?1处的留数。4z?1解:因为z?1以z?1为一级零点,而sin1?0,因此f?z?以z?1为一级极点。Res?f?z?,1??sinz?z4?1?z?1zz?1?sinz4z3z?1?1sin14例2:求函数f?z??e在z?0处的留数解:z?0是f?z?的本性奇点,因为f?z??ez?1z???111z2zn?111???e?e??1?z??????????1?????????????2n??n?1!??z2!z2!n!z??z1z?0?z???1111??????????n?1!n!2!2!3!所以C?1?1?可得Res?f?z?,0??1?111??????????n?1!n!2!2!3!第7章傅里叶变换通过一种途径使复杂问题简单化,以便于研究。定义:对满足某些条件的函数f?t?在???,???上有定义,则称F?????????f?t??e?i?tdt为傅里叶变换。同时f?t???????f?t??ei?td?为傅里叶逆变换注:①傅里叶变换是把函数f?t?变为函数F???②傅里叶逆变换是把函数F???变为函数f?t?③求傅里叶变换或傅里叶逆变换,关键是计算积分④两种常见的积分方法:凑微分、分部积分复习积分:①?e?xdx?1??e?xd??x??e?x????0?②?sin?7x?1?dx?1?cos?77?sin?7x?1?d?7x?1??x?1?7?2????2?3③x?e3x?3dx?13x2?313x2?3e3x2?edx2?26?ed3x?3?6④?x3exdx?x3ex??exd?x3??x3ex?3?exx2dx?x3ex?3?exx2??exd?x2???x3ex?3exx2?6?exxdx?x3ex?3exx2?6?xex??exdx??x3ex?3exx2?6xex?6ex⑤?x2sinxdx?x2sinx??sinxd?x2??x2sinx?2?xsinxdx?x2sinx?2?xsinx??sinxdx??x2sinx?2xsinx?2cosx注:?u?vdx?u?v??udv例1:求f?t????1t?s?0t?s的F???F???????f?t??e?i?t??dt???s?i?ts?i?t????0?edt???s1?edt??s0?e?i?tdt?i??se?i?t?sd??i?t?解:?i?ts?e?i?s?i?i?s??e?ei?s??2sin?s???例2:求f?t????0t?0?e??tt?0???0?的F???F?????????f?t??e?i?tdt??00?e?i?tdt?????0e??te?i?t?dt解:????????i??t0edt????1i?e????i??t??0???i??2??2?-函数定义:如果对于任意一个在区间???,???上连续的函数f?t?,???0??t?t0?f?t?dt?f?t0?,则称??t?为?-函数。例1:求?-函数的F???解:F????????i?t??????t?edt?????t?0?e?i??t?0??e?i?t?t?0?1恒有例2:求正弦函数f?t??sin?0t的傅氏变换F?????f?t??e?i?tdt??????sin?0t?e?i?tdt????ei?0t?e?i?0t?i?t???edt??2i解:1???i????0?t??e?e?i????0?tdt2i??1??2??????0??2??????0??2i?i???????0???????0??????☆??t?????1F???F???1????2??????1第8章拉普拉斯变换设f?t?在t?0时有定义
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推荐:    i的i次方等于多少,写成x+yi的形式如题:i^i=?写成x+yi的形式,其中要求x和y都是实数.我知道i的平方=-1,为什么i的i次访也是-1,怎么个计算的过程呢?指数是虚数的清跨国能不嫩理解。
小然然0331
令i^i=a则两边取自然对数ln(i^i)=lnalna=ilni而由复变函数lni=ln|i|+πi/2=πi/2,所以lna=i*πi/2=-π/2,所以a=e^(-π/2),即i^i=e^(-π/2)
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扫描下载二维码i^i是多少rti是虚数单位
黎约践踏2195
令i^i=a则两边取自然对数ln(i^i)=lnalna=ilni而由复变函数lni=ln|i|+πi/2=πi/2,所以lna=i*πi/2=-π/2,所以a=e^(-π/2),即i^i=e^(-π/2).
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