write a method that takes an int k argument and returns as d

write a method that takes an int k argument and returns as double the sum of first k terms of the series: 1+ (1/2) - (1/3) + (1/4) - (1/5) ...................... using java

Solution

you can just use this without complicating the code-

public static double sum(int k)

{
if (k<=1)
return (double) k;
return ((k%2==0)? 1 : -1)*(1/(double)k) + sum(k-1);
}

Here,for k=6

sum(6)
1/6 + sum(5)
sum(5)
-1/5 + sum(4)
sum(4)
1/4 + sum(3)
sum(3)
-1/3 + sum(2)
sum(2)
1/2 + sum(1)
sum(1) = 1

finally,
sum(6) = 1 + 1/2 - 1/3 + 1/4 - 1/5 + 1/6

Thankyou....