Mathematics
Implicit Differentiation and Related Rates Problems
Quick fact
Implicit differentiation lets you find dy/dx for equations like x² + y² = 25 by differentiating both sides and solving for dy/dx, even though y is never explicitly defined. This technique, powered by the chain rule, is the same tool that builds related rates equations—where quantities change together over time.
Why this is interesting
You can find the slope of a circle without ever solving for y. And you can know how fast a ladder slides down a wall just by knowing how fast its base moves—without measuring the ladder's speed directly.