Question

用matlab如何编写牛顿迭代法问题，谢谢

X^3-X-1=0在闭区间【1,2】内的近似根 要求精度达到10^(-5)

Answer 1

function
[
A
]
=
cal(
a,b,v
)%a,b表示区间，v是
精度
i=1;
x
=
(a+b)/2;
A=[i
x];
t
=
x-(x^3-x-1)/(3*x^2-1);%迭代函数
while(abs(t-x)>v)
i=i+1;
x
=
t;
A
=
[A;i
x];
t
=
x-(x^3-x-1)/(3*x^2-1);%迭代函数
end
A
=
[A;i+1
t];
end
运行结果:
>>
format
long;
>>
cal(1,2,0.00001)
ans
=
1.000000000000000
1.500000000000000
2.000000000000000
1.347826086956522
3.000000000000000
1.325200398950907
4.000000000000000
1.324718173999054
5.000000000000000
1.324717957244790

Answer 2

超过计算范围或精度。