How can we calculate coords of the end point if we know start point, distance and angle?-CodePudding

We know the start point, the angle and the distance between start and end points.

let x1 = 500;
let y1 = 500;
let angle = 45;
let distance = 100;

How can we calculate the coordinates of the end point?

It must be some method like Math.atan2...

CodePudding user response：

found it

let angle = 45, distance = 100, x1 = 500, y1 = 500;
let x2 = Math.round(Math.cos(angle * Math.PI / 180) * distance   x1);
let y2 = Math.round(Math.sin(angle * Math.PI / 180) * distance   y1);
console.log(x2, y2);

CodePudding user response：

Using Javascript, given the theta angle, and the length of the hypotenuse, find the opposite and adjacent sides:

let x1 = y1 = 500, // starting point
  hyp = 100, // hypotenuse
  theta_deg = 45, // theta angle in degrees
  rad = (parseFloat(theta_deg) * Math.PI) / 180, // convert deg to radians
  
  // opp = hyp * sin(θ)
  opp = Math.round((hyp * Math.sin(rad)) * 100) / 100, // opposite side
  
  // adj = √( (hyp * hyp) - (opp * opp) )
  adj = Math.round((Math.sqrt((hyp * hyp) - (opp * opp))) * 100) / 100, // adjacent side
  x2 = x1   adj, y2 = y1   opp; // end point

console.log('opposite side:', opp, ' adjacent side:', adj);
console.log('end point coord. = x2:', x2, ' y2:', y2);

Note: degrees must be converted to radians before applying to Javascript Math sine methods.

let deg = 45;
let rad = (parseFloat(deg) * Math.PI) / 180;
// 0.7853981633974483