x³-3x+1 = 0
Try substituting x=0 to see if we get close to 0
0³-3·0+1 = 1
x=0 gives 1, too big
Try 1
1³-3·2+1
-1
x=1 gives -1, too small
Try something in between 0 and 1
Try .5
.5³-3·(.5)+1 = -.375
x=-.375 is closer to 0, but still too small
So we try something in between 0 and .5, closer to .5,
Try .3
.3³-3·(.3)+1 = .127
.127 is closer to 0, but it's too big
So we try something in between .3 and .5, closer to .3
Try .35
.35³-3·(.35)+1 = -.007125
Nope, that's closer to 0, but it's too small
So we try something in between .3 and .35, closer to .35
Try .345
.345³-3·(.345)+1 = .006063635
Nope, that's closer to 0, but it's too big
So we try something in between .345 and .35,
closer to .345,
Try .347
.347³-3·(.347)+1 = .00078192
Nope, closer to 0, but still too big
So we try something in between .347 and .35,
closer to .347
Try .348
.348³-3·(.348)+1 = .0018558
Nope, not closer to 0, still too big
So we try something in between .347 and .38,
closer to .347
Try .3472
.3472³-3·(.3472)+1 = .00025421
Nope, closer to 0, still too big
So we try something in between .3472 and .345,
but much closer to .3472 since .00025421 is much
closer to 0 than -.007125.
So try .3473
.3473³-3·(.3473)+1 = -.000009615
That's a lot closer to 0 than when we tried .3472
So we choose something much closer to .3473 than to .3472.
Se we can stop there.
To four decimal places, it's .3473
Edwin