两道复数计算题1.((3-4i)/(1+2ii))+(2+i^15)-(1-i)^62.i+2i^2+3i^3+.+359i^359不小心多大了个i

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两道复数计算题1.((3-4i)/(1+2ii))+(2+i^15)-(1-i)^62.i+2i^2+3i^3+.+359i^359不小心多大了个i
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两道复数计算题1.((3-4i)/(1+2ii))+(2+i^15)-(1-i)^62.i+2i^2+3i^3+.+359i^359不小心多大了个i
两道复数计算题
1.((3-4i)/(1+2ii))+(2+i^15)-(1-i)^6
2.i+2i^2+3i^3+.+359i^359
不小心多大了个i

两道复数计算题1.((3-4i)/(1+2ii))+(2+i^15)-(1-i)^62.i+2i^2+3i^3+.+359i^359不小心多大了个i
答:
1)
(3-4i)/(1+2i)+(2+i^15)-(1-i)^6
=(3-4i)(1-2i)/[(1+2i)(1-2i)]+[2+i*(i^2)^7]+(1-2i+i^2)^3
=(3-10i+8i^2)/(1-4i^2)+(2-i)+(-2i)^3
=(-5-10i)/5+2-i+8i
=-1-2i+2+7i
=1+5i
2)
S=i+2i^2+3i^3+.+359i^359
两边同乘以i得:
iS=i^2+2i^3+3i^4+...+359i^360
两式相减:
S-iS=i+i^2+i^3+.+i^359-359*(i^2)^180
(1-i)S=i(1-i^359)/(1-i)-359=(i+i^2)(1-i^360/i)/2-359
(1-i)S=(i-1)(1-1/i)/2-359=(i-1)(1+i)/2-359=(-1-1)/2-359=-360
S=-360/(1-i)=-360(1+i)/2=-180-180i
所以:
i+2i^2+3i^3+.+359i^359=-180-180i