Graph an equation without x or y variables

plotly.js
1

Can not find information on how to graph an equation that does not contain x or y variables. Trying to graph the following equation:
N= (v*12) /(3.1415 * D)
Will assign D a value from a dropdown list.
How do I assign the N and v variables to the x and y axis.

2

Hi,

Welcome to the community! :slight_smile:

You need to create a range of values for v, then apply the equation for N. One way to do it in js is:

const range = (start, stop, step) => {
    let v=start
    const array = []
    while(v <= stop){
        array.push(v);
        v=v+step
    }
    return array;
}

// For example
const v = range(0, 10, 0.5);
const Nfunc = (v, D) => 12 * v / (Math.PI * D); // I assume you want Pi = 3.1415....

// Then...
const N = v.map(x => Nfunc(x, D));
3

Thanks,
Still having trouble making this work. Need a complete working example with html, script code.

4

Try this:

<head>
	<script src='https://cdn.plot.ly/plotly-2.11.1.min.js'></script>
</head>

<body>
	<div id='myDiv'></div>
</body>

 <script>
  const range = (start, stop, step) => {
    let v=start
    const array = []
    while(v <= stop){
        array.push(v);
        v=v+step
    }
    return array;
  }

  // For example
  const D = 1.0;
  const v = range(0, 10, 0.5);
  const Nfunc = (v, D) => 12 * v / (Math.PI * D); // I assume you want Pi =   3.1415....

  // Then...
  const N = v.map(x => Nfunc(x, D));

  const trace1 = {
    x: v,
    y: N,
    mode: 'markers',
    type: 'scatter'
  };

  const data = [trace1];

  Plotly.newPlot('myDiv', data);
</script>
5

Still getting a JavaScript error that range is not defined.

<!DOCTYPE html>
<html>

<head>
	<script src='https://cdn.plot.ly/plotly-2.11.1.min.js'></script>
</head>

<body>
	<div id='myDiv'></div>
</body>

 <script>
  

  // For example
  const D = 1.0;
  const v = range(0, 10, 0.5);
  const Nfunc = (v, D) => 12 * v / (Math.PI * D);

  // Then...
  const N = v.map(x => Nfunc(x, D));

  const trace1 = {
    x: v,
    y: N,
    mode: 'markers',
    type: 'scatter'
  };

  const data = [trace1];

  Plotly.newPlot('myDiv', data);
</script>
</html>
6

Yeah, but you deleted this part from my example…

7

Thanks,
That worked.