Hello Guys,For my homework I must write a shell script to do this serie,


I know that I must use the "bc" for that, but for the script's itself i have no idea,(beginner)


Can you plz just help me for have some idea?
Thanks


I wrote a script but it did not worked

#!/bin/sh
echo "Input number"
read n
counter=0
ans=1
while [ $counter -ne $n ]
do
ans=`expr 4*(-1/(2*$counter+1))`| bc -l
counter=`expr counter+1`
done

echo "the sum of the series is :-$ans"

First. The input to bc should be an expression, not a computed value.
Second. The 'expr' command requires the variables and operators to be separated by space.
Three,
You initialize ans to 1, but change it anyway before it is used, and at the end, you print it with a literal that suggests that you have summed the value of each expression calculated, but nowhere do you accumulate the answer.
You need to add
and change the last line to echo total instead of ans.