lovecoding
/
W250913


			
				
					
						
						
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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 f(n){
            var a = Math.pow(-1,n-1) * (1/(2*n-1));
            return a;
        }

        function f2(n){
            var sum = 0;
            for(var i=1;i<=n;i++){
                sum += f(i);
            }
            return sum*4
        }
        console.log(f2(100));
        console.log(f2(500));
        console.log(f2(1000));
        console.log(f2(10000));
    </script>
</body>
</html>