JavaScript: SyntaxError missing ) after argument list

问题

var quadraticFormula = function(a, b, c) {

        console.log((-b + sqrt( (b*b) - 4 * a * c)) / 2a) };

quadraticFormula(2,2,2)

I am a beginner trying to make a simple quadratic equation calculator on javascript. I keep on getting a syntax error message saying "missing ) after argument list". What is wrong with my code?

回答1:

Try adding a * sign in 2a:

var quadraticFormula = function(a, b, c) {

        console.log((-b + Math.sqrt( (b*b) - 4 * a * c)) / (2*a));

};

Also sqrt is part of Math so invoke it with Math.sqrt. Notice that quadraticFormula(2,2,2) will print NaN as it will try to do the square root of a negative number: (2*2) - 4 * 2 * 2.

Edit:
I wrapped 2*a inside () to correct the quadratic formula.

来源：https://stackoverflow.com/questions/31171211/javascript-syntaxerror-missing-after-argument-list