# Thread: approximate zero with Newton

1. ## approximate zero with Newton

Im stuck on this problem:

5cosx-x=0; they ask to use a graphing utility to approximate the answer.

2. You can approximate it by Newton's method. Graph it and see where it crosses the x-axis.

3. Originally Posted by >_<SHY_GUY>_<
Im stuck on this problem:

5cosx-x=0; they ask to use a graphing utility to approximate the answer.
Depending on your graphing utility the commands are different.

Here is maple 11.

You could also "guess" the x intercepts by looking at the graph

I hope this helps.

4. Originally Posted by TheEmptySet
Depending on your graphing utility the commands are different.

Here is maple 11.

You could also "guess" the x intercepts by looking at the graph

I hope this helps.

what if it is on the interval (0, 2pi]?

5. Originally Posted by >_<SHY_GUY>_<
what if it is on the interval (0, 2pi]?

The graph shows from $[-2\pi,2\pi]$ so just ignore the part of the graph to the left of the y axis.

So the only root would be

$x \approx 1.30644$