✔ 最佳答案
draw the graph
http://in.geocities. com/myisland8132/Boo k2.pub
we see that
there are roots between [0.1,1] and [2,3] use netwon's method to find the roots
let f(x)=2sin x -x+ln x
df(x)/dx=2cosx-1+1/x
x(n+1)=x(n)-f(x(n))/ f'(x(n))
x(n+1)=x(n)-[2sin x -x+ln x]/[2cosx-1+1/x]
let x(0)=0.1
interation
x(n)
x(n+1)
0
0.1
0.300447369
1
0.300447
0.515376023
2
0.515376
0.587193636
3
0.587194
0.592067109
4
0.592067
0.59208731
5
0.592087
0.59208731
6
0.592087
0.59208731
7
0.592087
0.59208731
8
0.592087
0.59208731
9
0.592087
0.59208731
10
0.592087
0.59208731
11
0.592087
0.59208731
12
0.592087
0.59208731
13
0.592087
0.59208731
14
0.592087
0.59208731
15
0.592087
0.59208731
16
0.592087
0.59208731
17
0.592087
0.59208731
18
0.592087
0.59208731
19
0.592087
0.59208731
20
0.592087
0.59208731
21
0.592087
0.59208731
22
0.592087
0.59208731
23
0.592087
0.59208731
24
0.592087
0.59208731
25
0.592087
0.59208731
let x(0)=2
interation
x(n)
x(n+1)
0
2
2.38410603
1
2.384106
2.314731096
2
2.314731
2.312744888
3
2.312745
2.312743182
4
2.312743
2.312743182
5
2.312743
2.312743182
6
2.312743
2.312743182
7
2.312743
2.312743182
8
2.312743
2.312743182
9
2.312743
2.312743182
10
2.312743
2.312743182
11
2.312743
2.312743182
12
2.312743
2.312743182
13
2.312743
2.312743182
14
2.312743
2.312743182
15
2.312743
2.312743182
16
2.312743
2.312743182
17
2.312743
2.312743182
18
2.312743
2.312743182
19
2.312743
2.312743182
20
2.312743
2.312743182
21
2.312743
2.312743182
22
2.312743
2.312743182
23
2.312743
2.312743182
24
2.312743
2.312743182
25
2.312743
2.312743182
so the roots of 2sin x -x+ln x=0 are 0.5921 and 2.3127