## 17Calculus Vector Functions - Equations

This page contains the full list of vector function equations including links to the pages where they are discussed and derived. Which equation you use will depend on the data you have to work with. We start by giving the variables and their names.

Variables

parametric equations

$$x(t),~y(t),~z(t)$$

$$\vec{r}(t) = x(t)\vhat{i} + y(t)\vhat{j} + z(t)\vhat{k}$$

vector function in terms of the arc length parameter, s

$$\vec{r}(s) = x(s)\vhat{i} + y(s)\vhat{j} + z(s)\vhat{k}$$

Note - When the variable s is used on this page, it refers to the arc length parameter.

Equations

velocity

$$\vec{v}(t) = \vec{r}'(t)$$

basic acceleration

$$\vec{a}(t) = \vec{v}'(t) = \vec{r}''(t)$$

unit tangent vector

$$\displaystyle{ \vhat{T}(t) = \frac{\vec{r}'(t)}{ \| \vec{r}'(t) \| } }$$

$$\displaystyle{ \vhat{T}(t) = \frac{\vec{v}(t)}{ \| \vec{v}(t) \| } }$$

principal unit normal vector

$$\displaystyle{ \vhat{N}(t) = \frac{d\vhat{T}/dt}{ \| d\vhat{T}/dt \| } }$$

acceleration vector

$$\vec{a}(t) = a_{\vhat{T}}\vhat{T} + a_{\vhat{N}}\vhat{N}$$

tangential component of acceleration

$$a_{\vhat{T}} = \vec{a} \cdot \vhat{T}$$

$$\displaystyle{a_{\vhat{T}} = \frac{\vec{a} \cdot \vec{v}}{\|\vec{v}\|} }$$

$$a_{\vhat{T}} = \| \vec{v} \|'$$

normal component of acceleration

$$a_{\vhat{N}} = \vec{a} \cdot \vhat{N}$$

$$a_{\vhat{N}} = \|\vec{v}\| \|\vhat{T}'\|$$

$$\displaystyle{a_{\vhat{N}} = \frac{\|\vec{v} \times \vec{a}\|}{\|\vec{v}\|} }$$

$$a_{\vhat{N}} = \sqrt{\|\vec{a}\|^2 - a_{\vhat{T}}^2}$$

You CAN Ace Calculus

 vectors vector functions projectile motion unit tangent vector principal unit normal vector acceleration components arc length arc length parameter curvature

### Calculus Topics Listed Alphabetically

Single Variable Calculus

Multi-Variable Calculus

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