数学题在线解答x

来源:学生作业帮助网 编辑:作业帮 时间:2024/04/25 21:09:28

数学题在线解答x
数学题在线解答x<0,且X-1/X=根号5求有理式(X的十次方+x的六次方+X的四次方+1)/(x的十次方+x的8次方+X的2
次方+1)的值

数学题在线解答x
x-1/x=根号5
(x-1/x)^2=5,x^2+1/x^2-2=5,x^2+1/x^2=7
(x^2+1/x^2)^2=49,x^4+1/x^4+2=49,x^4+1/x^4=47
(x^10+x^6+x^4+1)/(x^10+x^8+x^2+1)
=[x^2(x^8+x^4+x^2+1/x^2)]/[x^4(x^6+x^4+1/x^2+1/x^4)]
=[(x^8+x^4)+(x^2+1/x^2)]/[x^2(x^6+1/x^2)+(x^4+1/x^4)]
=[x^6(x^2+1/x^2)+(x^2+1/x^2)]/{x^2[(x^6+1/x^2)+(x^4+1/x^4)]}
=[(x^6+1)(x^2+1/x^2)] / {x^2[x^2(x^4+1/x^4)+(x^4+1/x^4)]}
=[(x^6+1)*7] / [x^2(x^2+1)(x^4+1/x^4)]
=[(x^6+1)*7] / [x^2(x^2+1)*47]
=[7(x^2+1)(x^4-x^2+1)] / [47x^2(x^2+1)]
=[7(x^4-x^2+1)] / [47x^2]
=7(x^2-1+1/x^2)/47
=7(x^2+1/x^2-1)/47
=7(7-1)/47
=42/47