lovecoding
/
web0715


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        function piNum(n){
            var sumNum = 0;
            for(var i=1;i<=n;i++){
               sumNum +=  Math.pow(-1,i-1)*(1/(2*i-1));
            }
            return sumNum * 4;
        }
        
        console.log(piNum(100));
    </script>
</body>

</html>