Math.cos():返回以弧度為單位的數字的餘弦值
function getCircleX(radians, radius) { return Math.cos(radians) * radius; } console.log(getCircleX(1, 10)); // Expected output: 5.403023058681398 console.log(getCircleX(2, 10)); // Expected output: -4.161468365471424 console.log(getCircleX(Math.PI, 10)); // Expected output: -10