Explore a comprehensive video tutorial on the definition of derivatives and related concepts from Stewart Calculus 7th edition. Learn through multiple examples, including the derivative of x^(2/3) using the definition, the necessity of the chain rule, and the derivative of x+abs(x). Practice sketching f' from f with numerous exercises from section 2.8. Gain a deeper understanding of calculus concepts through clear explanations and step-by-step problem-solving techniques.