javascript - 二次计算器给出 Nan

Question

我正在编写一个 react 应用程序来求解二次公式。当我输入 a=1 b=7 c=10 或任何有效的二次数时，它会返回 NaN[Object]NaN。有人可以帮忙吗，这是我的代码:

  quadraticFormula(a, b, c) {
    var root = -b + Math.sqrt(b, 2) - (4 * a * c);
    var plusAnswer = (-b + Math.sqrt(root))/(2*a);
    var minusAnswer = (-b + Math.sqrt(root))/(2*a);

    document.getElementById('answers').innerHTML = plusAnswer + <br/> + minusAnswer;
  }

Answer 1

您的公式 root中不正确。应该是Math.sqrt((b * b) - (4 * a * c))

此外，您没有使用 -在minusAnswer .

function quadraticFormula(a, b, c) {
  var root = Math.sqrt((b * b) - (4 * a * c))
  var plusAnswer = (-b + root) / (2 * a)
  var minusAnswer = (-b - root) / (2 * a)

  document.getElementById('answers').innerHTML = plusAnswer + <br/> + minusAnswer;
}

HTH