C program to compute the sum of the following series up to nth term (take n as use input): Total = 1 * 3 + 11 * 13 + 21 * 23 + 31* 33 + … How can I solve this?

Design a quick return four bar mechanism that will have time ratio of tr 1: 1.25 . the output link should scan 60° angle for a full crank rotation . the length of output link is 5.0 em 1)-find the length of the other links and draw the mechanism .(write down your steps) 2)-does the mechanism satisfy the grashof's condition. 3)-find the max and min transmission angles over the range of motion using graphical technique