Visual proofs using dynamic geometry software

The dissertation is divided into two main parts. The first part defines the concept of dynamic visual proof and is placed in the context of proving in mathematics as a subject of science and in mathematics as a subject taught at school. The digital component of the dissertation is a collection of 19 applets with dynamic visual proofs created in the GeoGebra program and arranged in thematic chapters in the so-called GeoGebra-Book, available on-line on geogebra.org. In the second part of the work the research focused on the use of dynamic visual proofs in secondary school mathematics lessons and their influence on fulfilment of educational objectives is described. This a qualitative research where a case study focused on the detailed study of a mathematics teacher who uses dynamic visual proofs in her class. To identify educational objectives, a revised Bloom's taxonomy was chosen