[spec] clean up
[notes.git] / spec / vectors.md
index 3a940e323edd85211626ae2817ab4cef1c56c375..ef987fad121a2e3ecbe4a2770d19fdcab8bf6f49 100644 (file)
@@ -193,3 +193,11 @@ $$\boldsymbol{r}(t)=x\boldsymbol{i}+y\boldsymbol{y}$$
 - If $\boldsymbol{r}(t)$ represents position with time, then the graph of endpoints of $\boldsymbol{r}(t)$ represents the Cartesian path.
 - Domain of $\boldsymbol{r}(t)$ is the range of $x(t)$
 - Range of $\boldsymbol{r}(t)$ is the range of $y(t)$
+
+## Vector calculus
+
+### Derivative
+
+Let $\boldsymbol{r}(t)=x(t)\boldsymbol{i} + y(t)\boldsymmbol(j)$. If both $x(t)$ and $y(t)$ are differentiable, then:
+
+$$\boldsymbol{r}(t)=x(t)\boldsymbol{i}+y(t)\boldsymbol{j}$$