### message | statement | equation:

Differential equation
* are equations
  - mathematical constructs which define the rates of changes of variables
  - the most challenging and important problems in mathematics
* arising from first principle models are generally nonlinear.
* can be of any order and complexity.
* describe all types of movement
* give a formula for the derivative- the change in a quantity per unit time.
  - extension of integral calculus
* is, in some sense, advanced advanced calculus.
* make reaction time a natural prediction of connectionist models.

Drake equation
* Most drake equations have real values.
* have practical values.
* have real practical values

Famous equation
* Most famous equations describe population growth.
* describe growth.
* describe logistic growth
* explain facts.

Linear equation
* have exactly one solution.
* is an equation
* play a fundamental role in the development of calculus.

Logistic equation
* Most logistic equations describe growth.
* Most logistic equations describe logistic growth

Mathematical equation
* Most mathematical equations explain observations.
* Some mathematical equations describe motion
  - properties
  - represent plots
* are just like sentences.
* represent reality
  - the physics along the drill holes

Photosynthesis equation
* Some photosynthesis equations explain photosynthesis.
* is the reverse of the summary equation for respiration.

Physics equation
* can describe any piece of matter.
* involve tensors of the same rank.

Quadratic equation
* are the first building block on the road to higher mathematics.
* form the basic foundation for mathematical literacy in calculus and algebra.

Regression equation
* Most regression equations come from data in observational studies.
* is an equation

Explanation
* are phrased as ultimate causes that explain why a behavior has evolved
  - speech acts
  - statements
  - thinking
* base on evidence.
* come from theories.
* describe effects
  - greenhouse effects
* explain mysteries
  - results
* include facts
* incorporate knowledge.
* involve introductions.
* support facts.
* use information.

### message | statement | explanation:

Clarification
* form of education, but it comes in response to conversation.
* is an interpretation
  - the process of removing suspended solids from water
* way to remove particles from stock to make it as clear as possible.

### message | statement | explanation:

Definition
* Fixed costs are expenses the business incurs before any sales are made.
* Transvestite a person who dresses in the clothes of the opposite sex.
* applies to rules.
* are human inventions
  - rules for the translation of one language into another
  - the attitudes and meanings that one attaches to a given behavior
* bases on hypotheses.
* gives information.
* includes comparison.
* incorporates features.
* is an explanation
* makes more senses
* play an important role in academic writing in all disciplines.
* product which contains herbs which are generally recognized as safe.
* provides descriptions
  - references
* publishes in journals.
* ratio A pair of numbers that compares different types of units.
* relates to ideas.
* requires clarification.

### message | statement | explanation | definition:

Operational definition
* describe concepts which can be measured in some way.
* describes how one variable relates to another.

Evolutionary explanation
* are highly fashionable for all manner of sin.
* can never explain man's higher powers.