已知x^2-x-1=0,求x^4+2x+1⼀x^5

2024-12-24 11:52:47
推荐回答(3个)
回答1:

解析:
已知x²-x-1=0,那么:x²=x+1
所以:(x^4 +2x+1)/(x^5)
=(x^4 +x +x+1)/(x^5)
=(x^4 +x +x²)/(x^5)
=(x³+x+1)/(x^4)
=(x³+x²)/(x^4)
=(x+1)/(x²)
=1

回答2:

利用公式法解一元二次方程,解得X=【(正负√5+1)/2】,把X带入就可得结果

回答3:

x^2-X-1=0
b^2-4ac=(-1)^2-4×1×(-1)
=1-(-4)
=5
x=-b±√b^2-4ac/2a
=1±√5/2