Affiliation:
1. Faculty of Economics and Business , University of Zagreb , Croatia
Abstract
Abstract
The quadratic trend is a statistical model described by the quadratic function. Finding its extremum (also called the vertex or the turning point) using differential calculus or completing the square method is very well known in the literature. In this paper, a new method for finding the extremum of the quadratic function, based on a simple mathematical inequality is proposed. In comparison with the other two known methods, our method does not require the differentiability assumption and it takes fewer steps than completing the square method. Also, it is shown how the turning point for the quadratic trend can be applied in forecasting the unemployment rate in Croatia in the first quarter of 2019. The obtained conclusions are equal to the conclusions obtained in the usual way by using forecasting software.
Reference19 articles.
1. 1. Aude, H. T. R. (1938). The Solutions of the Quadratic Equation Obtained by the Aid of the Trigonometry. National Mathematics Magazine, Vol. 13, No. 3, pp. 118-121.10.2307/3028750
2. 2. Bossé, M. J., Nandakumar, N. R. (2005). The factorability of quadratics: Motivation for more techniques (section A). Teaching Mathematics and its Applications, Vol. 24, No. 4, pp. 143-153.10.1093/teamat/hrh018
3. 3. Didis, M. G., Erbas, A. K. (2015). Performance and Difficulties of Students in Formulating and Solving Quadratic Equations with One Unknown. Educational Sciences: Theory and Practice, Vol. 15, No. 4, pp. 1137-1150.
4. 4. Dimian, G. C., Begu, L. S., Jablonsky, J. (2017). Unemployment and labour market mismatch in the European Union Countries, Zbornik radova Ekonomskog fakulteta u Rijeci: časopis za ekonomsku teoriju i praksu, Vol. 35, No. 1, pp. 13-44.
5. 5. Dumičić, K. (2015). Developing Forecasting Models for Unemployment Rate by Gender: Cross Countries Comparison. Proceedings of the World Statistics Congress – WSC ISI'2015, Rio de Janeiro, 2015. Available at http://www.isi2015.org/components/com_users/views/registration/tmpl/media/uploadedFiles/paper/2840/10592/PP-A10-P12-S.pdf [06 November 2019].