equationOfCenter function
Implementation
num equationOfCenter(num M) {
var firstFactor = 1.9148 * math.sin(M);
var secondFactor = 0.02 * math.sin(2 * M);
var thirdFactor = 0.0003 * math.sin(3 * M);
return rad * (firstFactor + secondFactor + thirdFactor);
}