Document Type : Research Paper

**Authors**

Department of Mathematics, Sahand University of Technology, Tabriz, Iran.

**Abstract**

This paper deals with a typical Caputo fractional differential equation. This equation appears in important applications such as modeling of medicine distributed throughout the body via injection and equation for general population growth. We use the fixed point theory of concave operators in specific normed spaces to find a parameter interval for which the unique positive solution exists. Some properties of positive solutions are studied and illustrative examples are given.

**Keywords**

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July 2022

Pages 567-579

**Receive Date:**28 May 2021**Revise Date:**30 November 2021**Accept Date:**02 December 2021