UPAYA MENGEMBANGKAN KEMAMPUAN BERPIKIR KRITIS MELALUI PEMBELAJARAN MENGGUNAKAN BAHAN AJAR GEOMETRI ANALITIK BERBASIS GUIDED DISCOVERY

This research aims to develop students critical thinking skills through analytic geometry guided discovery basedteaching materials. This classroom action research involves three cycle stages: 1) planning; 2) acting and observing; 3) reflecting. The subjects of this study are 46 students of Mathematics Education, who takes courses analytic geometry in the second semester of academic year 2014/2015. The data are collected by test, interviews, observation, and documentation. Qualitative data analysis is supported by quantitative data analysis. The validity of the data using triangulation techniques. The results show that the student critical thinking skills increase through this teaching materials. It is seen from the increasing in critical thinking skills on each indicator that consider to: 1) Formulating the problem 42.935, 60.870, 78.261, 88.587; 2) Systematically thinking 28.804, 38.587, 51.630, 59.783; 3) Using the proofs in problem solving 22.826, 27.717, 34.783, 38.043; 4) It is not easy to give up the face of adversity 41.304, 53.804, 67.935, 80.978; and 5) Taking conclusions 35.326, 42.391, 68.478, 85.870.