Merge pull request #1058 from ShraddhaBhojane/master

added snippet VectorAngle

snippets/vectorAngle.md

@@ -0,0 +1,23 @@
+---
+title: vectorAngle
+tags: math,beginner
+---
+
+Returns the angle (theta) between two vectors.
+
+Use `Array.prototype.reduce()`, `Math.pow()` and `Math.sqrt()` to calculate the magnitude of each vector and the scalar product of the two vectors.
+Use `Math.acos()` to calculate the arccos and get the theta value.
+
+
+```js
+const vectorAngle = (x, y) => {
+  let mX = Math.sqrt(x.reduce((acc, n) => acc + Math.pow(n, 2), 0));
+  let mY = Math.sqrt(y.reduce((acc, n) => acc + Math.pow(n, 2), 0));
+  return Math.acos(x.reduce((acc, n, i) => acc + n * y[i], 0) / (mX * mY));
+};
+```
+
+```js
+vectorAngle([3, 4], [4, 3]); // 0.283794109208328
+```
+