Differential Equations formula reference

Exponential Decay Model

Solves a proportional decay law y′=−ky with positive rate k.

Open in editor
LaTeXy(t)=y_0e^{-kt}

Variables

  • y_0: initial value
  • k: decay constant
  • t: elapsed time

How to use this formula

Solves a proportional decay law y′=−ky with positive rate k.

Important notes

  • The model assumes the instantaneous decay rate is proportional to the current amount.
  • Half-life is ln(2)/k.

Quick example

With y0=100 and k=0.1, y(10)=100e^{-1}.

Applicability, worked calculation, and verification

Assumptions and domain checks

  • The model assumes the instantaneous decay rate is proportional to the current amount.
  • State the domain together with any initial or boundary conditions, and confirm the regularity assumptions required by the method.

Worked example

Input

Output

With y0=100 and k=0.1, y(10)=100e^{-1}.

Common mistakes

  • Before substituting values into Exponential Decay Model, map each variable to its definition and preserve every sign, exponent, subscript, and grouping mark.
  • Do not present a general solution as the requested solution before applying all initial or boundary conditions.

Continue the workflow

Use Exponential Decay Model in your own work

  1. Check the domainMatch the variables and assumptions to the problem before substituting values.
  2. Copy the exact notationPreserve grouping, signs, and exponents in y(t)=y_0e^{-kt}.
  3. Edit or convertOpen the expression in the LaTeX editor, then export it for your document or web page.

Review and verification

Last reviewed: 2026-07-23

Automated quality check: Kept noindex until the missing evidence is supplied.

Formula references

Frequently asked questions

What is the Exponential Decay Model used for?

Solves a proportional decay law y′=−ky with positive rate k.

Can I copy this formula as LaTeX?

Yes. Copy y(t)=y_0e^{-kt} or open it in the LaTeX editor.

What should I check before using it?

Confirm that each variable, unit, domain restriction, and assumption matches the problem.

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