As part of developmental research for an inquiry-oriented differential equations course, this study investigates the change in students' beliefs about mathematics. The discourse analysis has identified two different types of perspective modes--i.e., discourse of the third-person perspective and discourse of the first-person perspective--in the students' mathematical narratives, depending on their ways of positioning themselves with respect to mathematics. In the third-person perspective discourse, the students positioned themselves as passive recipients of mathematics that has been established by some external authority. In the first-person perspective discourse, the students positioned themselves as active mathematical inquirers and produced mathematics by interweaving their own mathematical ideas and experiences. Over the semester, students' mathematical discourse changed from third-person perspective narratives to first-person perspective narratives. This change in their discourse pattern is interpreted as an indication of change in their beliefs about mathematics. Finally, this article discusses the instructional features that promote the change.