作者 |
標題: 數學問題 |
阿呆 
IP Address:
[ 211.76.98.132 ] |
發表於: 2005/4/17 下午 03:51:27
我絕ㄉ這ㄍ題目很困難 怎ㄇ算都算不出來 可以幫忙解一下嗎? 因式分解(x+1)4次方+(X+3)4次方-272 順便問一下 如何將次 方ㄉ指數打在上面
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jack 
IP Address:
[ 203.69.252.172 ] |
回覆於: 2005/4/17 下午 04:46:14
2(x+5)(x-1)(x^2+4x+19)嗎?
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yjc 
IP Address:
[ 211.76.98.134 ] |
回覆於: 2005/4/17 下午 06:35:52
test (x+1)<SUP>4</SUP>+(x+3)<SUP>4</SUP>-272
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阿呆 
IP Address:
[ 211.76.98.133 ] |
回覆於: 2005/4/17 下午 07:54:56
那.......請問此題的過程是呢 因為我不太明白是如何才能化簡....可以幫忙一下 嗎??
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jack 
IP Address:
[ 203.69.252.172 ] |
回覆於: 2005/4/17 下午 08:56:14
(x+1)^4+(x+3)^4-272 =[(x+1)^2]^2-2(x+1)^2*(x+3)^2+[(x+3)^2]^2+2(x+1)^2*(x+3)^2-272 =[(x+1)^2-(x+3)^2]^2+2[(x+1)*(x+3)]^2-272 =[(x+1+x+3)(x+1-x-3)]^2+2(x^2+4x+3)^2-272 =[(2x+4)*(-2)]^2+2[(x+2)^2-1]^2-272 =16*(x+2)^2+2[(x+2)^2-1]^2-272 =2(x+2)^4-4*(x+2)^2+2+16(x+2)^2-272 =2(x+2)^4+12(x+2)^2-270 =2[(x+2)^2+15][(x+2)^2-9] =2(x^2+4x+19)(x^2+4x-5) =2(x+5)(x-1) (x^2+4x+19)
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小昭 
IP Address:
[ 14.0.227.177 ] |
回覆於: 2025/3/11 上午 09:25:31
x+1與x+3的中間(即x+2)為左右對稱 設t=x+2 (利用對稱,將t^3及t的係數正負抵消) (x+1)^4+(x+3)^4-272 =(t-1)^4+(t+1)^4-272 =(t^4-4t^3+6t^2-4t+1) +(t^4+4t^3+6t^2+4t+1)-2*136 =2(t^4+6t^2+1-136) =2((t^4+6t^2+9)-144) =2((t^2+3)^3-12^2) =2((t^2+3)-12)((t^2+3)+12) =2(t^2-9)(t^2+15) =2(t-3)(t+3)(t^2+15) =2(x-1)(x+5)(x^2+4x+19)
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