It's not unique in that there literally exist other computer algebra systems (CAS), sure. But it is unique in two meaningful ways:
1. It is arguably the most sophisticated CAS available. Open source tooling has crept up in performance and completeness in recent years, but Mathematica still dwarfs every open source system in performance and feature availability. Competing proprietary systems like Maple are capable of beating Mathematica in certain specific domains (like PDEs), but that leads me to my second point.
2. Mathematica isn't just a CAS. It also supports sophisticated data analysis and ingestion, visualization, (some) machine learning, natural language processing, speech recognition, signal processing, climatology, meteorology, geography, financial analysis, and limited forms of convex optimization.
1. It is arguably the most sophisticated CAS available. Open source tooling has crept up in performance and completeness in recent years, but Mathematica still dwarfs every open source system in performance and feature availability. Competing proprietary systems like Maple are capable of beating Mathematica in certain specific domains (like PDEs), but that leads me to my second point.
2. Mathematica isn't just a CAS. It also supports sophisticated data analysis and ingestion, visualization, (some) machine learning, natural language processing, speech recognition, signal processing, climatology, meteorology, geography, financial analysis, and limited forms of convex optimization.