Syftet med denna undersökning har varit att studera gymnasieelevers förståelse för funktionsbegreppet.Den teoretiska utgångspunkten har varit att studera elevernas förmåga att växla mellanolika representationsformer och studera deras förståelse för relationen mellan de olika representationerna.Elevernas förmåga att resonera har också varit en väsentlig del och därför har forskningenkring matematiskt resonemang också varit en viktig del i arbetet. För att nå ett resultat har treklasser på gymnasiet fått skriva ett test konstruerat för att svara mot uppsatsens syfte. Utövertestet intervjuades tre av eleverna för att det skulle finnas möjlighet att fånga elevernas förmågaatt resonera. Resultatet kom att visa att vissa elever har svårt att utföra växlingar mellan vissaolika representationer, men mellan andra är det betydligt enklare. Det framkom att eleverna varskolade i ett algoritmiskt tänkande, och att eleverna hade svårt att resonera fritt och kreativt kringfunktionsbegreppet, samt att eleverna hade svårt att skilja de närliggande begreppen ekvation ochfunktion. / The aim with this thesis has been to study Swedish high school students’ comprehension for theconcept of a function. The theoretical starting point has been to study the students’ ability tochange between different forms of representations of a function and study their comprehensionfor the relation between the different representations. The students’ ability to use mathematicalreasoning has also been a crucial part for the thesis, and therefore research on mathematicalreasoning has also been an important part. Three high school classes were given a test, whichsought to test their ability to change between different forms of representation. In addition to thetest three students were interviewed, so that the students’ ability to reason would be possible toanalyze. The results came to show that some students have difficulties to change between someof the representations but between others it’s far easier for them. The results also showed thatthe students were trained in algorithmically thinking, and that it was difficult to reason creativelyabout the concept of a function. The students also had trouble separating a function from therelated concept of equations.

The thesis discusses about the teacher's concept of teaching at teachers first grade of primary school and the possibilities of its transformation. In the theoretical part was to summarize the findings about which folders contains how the teacher's concept of teaching forms and which factors may cause changes in the teacher's concept of teaching. The aim of the empirical part of this thesis was to find out what the concepts of teaching have selected respondents. A partial aim of this study was to determine how the teacher's concept shaped and which factors affect the possible changes in the teacher's concept of teaching. Keywords: concept of teaching,teacher's concept properties, function of teaching concept, reflection, changes in the teaching concept, teacher, first grade of elementary school