해법
확장 16(x+3i)5⋅(3−4i)
해법
164(243+15x4)−1080x2+1215x−270x3+3x5+i16729+4(−x5−405x)+360x3+45x4−810x2
솔루션 단계
16(x+3i)5(3−4i)
(x+3i)5=x5+15ix4−90x3−270ix2+405x+243i
=16(3−4i)(x5+15ix4−90x3−270ix2+405x+243i)
(x5+15ix4−90x3−270ix2+405x+243i)(3−4i):3(x5−90x3+405x)+4(15x4−270x2+243)+i(3(15x4−270x2+243)−4(x5−90x3+405x))
=163(x5−90x3+405x)+4(15x4−270x2+243)+i(3(15x4−270x2+243)−4(x5−90x3+405x))
−4(x5−90x3+405x)+3(15x4−270x2+243)확대한다:−4x5+360x3−1620x+45x4−810x2+729
=163(x5−90x3+405x)+4(15x4−270x2+243)+i(−4x5+45x4+360x3−810x2−1620x+729)
3(x5−90x3+405x)+4(15x4−270x2+243)+(−4x5+360x3−1620x+45x4−810x2+729)i확대한다:3x5−270x3+1215x+60x4−1080x2+972−4ix5+360ix3−1620ix+45ix4−810ix2+729i
=163x5−270x3+1215x+60x4−1080x2+972−4ix5+360ix3−1620ix+45ix4−810ix2+729i
분수 규칙 적용: ca±b=ca±cb163x5−270x3+1215x+60x4−1080x2+972−4ix5+360ix3−1620ix+45ix4−810ix2+729i=163x5−16270x3+161215x+1660x4−161080x2+16972−164ix5+16360ix3−161620ix+1645ix4−16810ix2+16729i=163x5−16270x3+161215x+1660x4−161080x2+16972−164ix5+16360ix3−161620ix+1645ix4−16810ix2+16729i
16270x3=8135x3
1660x4=415x4
161080x2=2135x2
16972=4243
164ix5=4ix5
16360ix3=245ix3
161620ix=4405ix
16810ix2=8405ix2
=163x5−8135x3+161215x+415x4−2135x2+4243−4ix5+245ix3−4405ix+1645ix4−8405ix2+16729i
다시 쓰다 163x5−8135x3+161215x+415x4−2135x2+4243−4ix5+245ix3−4405ix+1645ix4−8405ix2+16729i 표준복합형태로: 163x5+1215x−270x3+4(15x4+243)−1080x2+164(−x5−405x)+360x3+45x4+729−810x2i
=163x5+1215x−270x3+4(15x4+243)−1080x2+164(−x5−405x)+360x3+45x4+729−810x2i