Talk:Time derivative

	Mathematics portal This article is within the scope of WikiProject Mathematics, a collaborative effort to improve the coverage of mathematics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.MathematicsWikipedia:WikiProject MathematicsTemplate:WikiProject Mathematicsmathematics articles
Mid	This article has been rated as Mid-priority on the project's priority scale.

Physics High‑importance

	Physics portal This article is within the scope of WikiProject Physics, a collaborative effort to improve the coverage of Physics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.PhysicsWikipedia:WikiProject PhysicsTemplate:WikiProject Physicsphysics articles
High	This article has been rated as High-importance on the project's importance scale.

Notational dispute[edit]

I dispute the sentence "Other shorthands include a subscripted t as in x_t." While subscript notation can be used to refer to derivatives, I've never seen it used for a time derivative. The reason is that the notation x_t is discrete-time notation for the level (not change) of x at time t.

Unless someone objects, I will delete this sentence. Please respond pro or con. Duoduoduo (talk) 19:46, 4 July 2010 (UTC)[reply]