please help :) something realated with cycles

pixie123

cyclic sum Posted by pixie123 today at 1:31 AM
hello everyone! i wanted to know if enyone can help me with this: i am learning pascal basics in school so i have one little problem with this:

i want to make programm where the 'x' value type user, and then the sum is calculated, but i dont know how to make formula for this

(1/2)+(3/2^2)+(5/2^3)+...+((2x-1)/2^x)

so the formula is ((2x-1)/2^x); for example: user types that x is 3;
then the programm puts 3 in x place; then 2; and then 1 and then all this sum together like this example where x is 3
((6-1)/8) + ((4-1)/4) + ((2-1)/2) = ...

so i want to create summing like this, i think it is something related with cycles, but i dont know for sure, so if anyone can help me i'll be grateful