How do you measure something that never stops changing?
Nature never stands still.
☕
Cooling
dT/dt = −k(T − T∞)
🌊
Oscillation
d²x/dt² = −ω²x
⚡
Circuit
L·dI/dt + RI = V
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Motion
F = m·d²x/dt²
For millennia, mathematics could only describe things at rest. But nature is never at rest. Everything changes. And sometimes — the rate of change depends on the thing itself. That is the heart of a differential equation.