Question

这是我的公式，没有得到正确的输出....我正在寻找有人必须贡献的月付款（以％的回报率）来获得他们的“未来价值”!!我做错了..我相信这很简单..谢谢。

//set default input text
var loanText = 100000;
var interestText = 10;
var yearsText = 1;

//restrict the input boxes to numbers and symbols
loan_txt.restrict = "0-9\\.";
interest_txt.restrict = "0-9\\.";
years_txt.restrict = "0-9\\.";
//
calculate_mc.onRollOver = function(){
    this.gotoAndPlay("over");
}
calculate_mc.onRollOut = function(){
    this.gotoAndPlay("out");
}
calculate_mc.onRelease = function(){
    if (loan_txt.text!="" && interest_txt.text!="" && years_txt.text!=""){
        loanPayments();
    }else{
        monthly_txt.text = "Please fill in all fields";
    }
}
//
loan_txt.onSetFocus = function() {
    if (loan_txt.text == loanText) {
        loan_txt.text = "";
    }
};
loan_txt.onKillFocus = function() {
    if (loan_txt.text == "") {
        loan_txt.text = loanText;
    }
};
interest_txt.onSetFocus = function() {
    if (interest_txt.text == interestText) {
        interest_txt.text = "";
    }
};
interest_txt.onKillFocus = function() {
    if (interest_txt.text == "") {
        interest_txt.text = interestText;
    }
};
years_txt.onSetFocus = function() {
    if (years_txt.text == yearsText) {
        years_txt.text = "";
    }
};
years_txt.onKillFocus = function() {
    if (years_txt.text == "") {
        years_txt.text = yearsText;
    }
};
loanPayments = function(){
    var loanAmount = loan_txt.text;
    var interestRate = (interest_txt.text)/100;
    var years = years_txt.text;
    var downPayment = 0;

    var monthRate = interestRate/12;
    var numPayments = years*12;
    var prin = loanAmount - downPayment;

    monthPayment = Math.floor((prin*monthRate)/(1-Math.pow((1+monthRate),(1*numPayments)))*100)/100;
                //form.NumberOfPayments.value=NumPayments
    var getDec = String(monthPayment).indexOf(".");
    var add0s = "";
    if(String(monthPayment).length +getDec == 2){
        add0s = "0";
    }else if(String(monthPayment).length +getDec == 1){
        add0s = "00";
    }
    trace(add0s);
    trace(monthPayment);
    monthly_txt.text = "$"+monthPayment+add0s;
}

Answer 1

monthPayment = (prin*monthRate) / (1-Math.pow(1+monthRate,-numPayments))

Flash数学“回报率”公式？迷茫！

1 个答案: