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import { float64equals } from "../utils/float64equals.ts";import { dot } from "./dot.ts";import { norm } from "./norm.ts";
export default function isBoomerang(points: number[][]): boolean {    if (points.length !== 3) return false;    const [[x1, y1], [x2, y2], [x3, y3]] = points;
    if (        (x1 === x2 && y1 === y2) ||        (x1 === x3 && y1 === y3) ||        (x3 === x2 && y3 === y2)    ) {        return false;    }    const vector1: [number, number] = [x2 - x1, y2 - y1];    const vector2: [number, number] = [x3 - x1, y3 - y1];    // return !float64equals(Math.abs(cos(vector2, vector1)), 1);    const innerProduct = dot(vector2, vector1);    return !float64equals(        Math.abs(innerProduct),        norm(vector2) * norm(vector1),    );}