How does an increasing/decreasing trend of 2d curve can be analysed
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a =

  Columns 1 through 9

    1.0265    1.5121    2.0447    2.5024    3.0697    4.0633    5.0202    6.1585    8.1711

  Columns 10 through 18

   10.2405   11.0000   12.0364   14.8711   20.3985   25.5645   30.4792   40.4400   50.9230

  Columns 19 through 21

   70.5175   79.0374  107.9006


x =

  Columns 1 through 9

   40.1157   30.0994   20.1416   18.7038   18.3298   18.3710   18.6200   20.2776   23.5150

  Columns 10 through 18

   26.7840   30.3027   34.3607   40.2961   53.4651   65.4319   79.5399   97.1246  114.1576

  Columns 19 through 21

  140.3374  148.4362  160.0000

a and x are data and i want to extract the increasing/decreasing trend of the curve in matlab.I would like to extract the increase/deccrease in point of a and the corresponding values of x..