7.1 In an experiment the variable x1 is changed for four times and the y1 corresponding to that is presented in the form below. Try to draw a straight line for it and make it best reflect the result of this experiment in least-square.(You only have to write down the mathematics model) 7.2 We have a system of linear eqations as below: Now we want to use unconstrained minimization method to get the result, try to set up the mathematics model and explain the theory. 7.3 Try to judge if this nonlinear programming is convex programming: 7.4 Try to use Fibonacci method to calculate the minimal point in siding-to-siding block [0,10] of the function given, requiring the length of block after shorten is equal or less than the 8% of the origin block. I'm not sure about the grammer but the basic meaning is translated, hopefully it could help you. :D