Explore the challenges and limitations of establishing real numbers through Cauchy sequences of rational numbers in this 29-minute mathematics lecture. Delve into the visualization of sequences in the plane, examine different notions of sequence convergence, and understand the concept of Cauchy convergence. Investigate the difficulties in setting up arithmetic with 'real numbers' using this approach, and gain insights into why this method falls short. Learn about the two distinct notions of convergence for sequences and discover the need for a complete and proper theory of real numbers. Enhance your understanding of foundational mathematical concepts and critically analyze common misconceptions in analysis courses.