Implement a function fractionSum(n) that calculates and returns the sum of the following sequence: 1/n + 1/(n−1) + 1/(n−2) + ⋅⋅⋅ + 1/2 + 1
For example, fractionSum(5) calculates the following sum: 1/5+1/4+1/3+1/2+1 And then returns 2.283333333333333
I haven't even started writing function just yet since I'm still stuck at trying to figure out the right loop expression. This is what I've done so far:
var sum =0;
var fraction = 1;
var number = parseInt(prompt("Enter an integer: ", "5"));
for ( var counter = 0; counter <= number; counter++) {
fraction /= (number - counter); // do I need to declare parseFloat here for decimal# ?
sum += fraction;
}
document.write("The total value is " + sum);
The number doesn't match up at all from the example. I'm not sure what the problem is here.
I'm pretty confused right now. I know this is basic problem but I has tried multiple codes and it still didn't come out right.
Thank you so much
You're reusing the fraction from the previous iteration and dividing it by the next value. You need a new fraction instead:
fraction = 1 / (number - counter);
Also, you need the strict counter < number condition in the loop to avoid division by zero.
In the loop, counter must be less than number else at the end there will be divison by 0, the result will be infinity. Try this
let sum = 0;
let i = 0;
let num = parseInt(prompt("Enter an integer: ", "5"));
for(i; i < num; i++ ){
frac = 1 / ( num - i);
sum+= frac;
}
I figured it out. This is what I got:
<script>
function fractionSum(number) {
var sum =0;
for (var counter= 0 ; counter < number; counter++) {
sum += 1/(number - counter);
}
return sum;
}
var number = parseInt(prompt("Enter the value of n: ", "5"));
sum = fractionSum(number);
document.write("The fraction sum of order " + number + " is " + sum);
</script>
Thank you guys, it was very helpful