Can you answer question no 51 in the attached image/////...........

The question is to find the sum of all odd terms...(1\1^2) + 1/3^2)....and so on..The strategy used here will be finding the sum of all even terms and then subtracting from the total sum...(1/2^2)+(1/4^2)+(1/6^2)....Taking 1/4 as common we get...(1/4)[1/1^2+1/2^2+1/3^2.....)Which equals(1/4)(π^2/6)...Therefore subtracting from the total sum...(3/4)(π^2/6)=(π^2/8)..hence the answer..