Session 09 - Implicit Differentiation and Logarithmic Differentiation

Engineering Context: Hidden Relationships in Complex Systems

In real-world engineering, systems are rarely bound by clean, explicit formulas, making the concepts from these notes essential for modeling complex physical relationships. Implicit differentiation is heavily used in mechanical engineering and robotics to map kinematics and joint velocities along geometric constraints, in thermodynamics to find rates of pressure change ($\frac{dP}{dV}$) within non-linear equations of state, and in cryptography to compute tangent lines on elliptic security curves. Meanwhile, logarithmic differentiation provides a shortcut for electrical and materials engineers to differentiate tedious, multi-factor formulas like signal decay or to isolate fractional rates of change ($\frac{y'}{y}$) for structural strain calculations, and it forms the bedrock of AI deep learning by converting computationally heavy probability products into simple addition layers during network training.

• Review common misconceptions and clarify key notations.

• Reflect on the physical modeling applications and mathematical setups.

• Verify calculations and mathematical reasoning.

• Core takeaways from Session 09 and overview of homework Knewton: Implicit Differentiation.