### Applet: A vector in three-dimensional space

#### Applet loading

A representation of a vector $\vc{a}=(a_1,a_2,a_3)$ in the three-dimensional Cartesian coordinate system. The vector $\vc{a}$ is drawn as a green arrow with tail fixed at the origin. You can drag the head of the green arrow with your mouse to change the vector. To help show the three dimensional perspective, a pink triangle connects the vector to its projection $(a_1,a_2,0)$ in the $xy$-plane (gray arrow). Purple vectors show the projections of $\vc{a}$ on each axis and represent the coordinates $a_1$, $a_2$, and $a_3$. You can also drag the heads of the purple vectors to change just one of the coordinates of the vector. Or drag the head of the gray vector in the $xy$-plane to change just the $x$ and $y$ coordinates.

#### Applet links

This applet is found in the pages

#### General information about three.js applets

The applet was made using three.js and requires Javascript as well as a browser that supports WebGL. For most three.js applets, you can drag with the mouse to rotate the view, drag with the right button to pan, and zoom in/out with the mouse wheel. Many applets contain points that you can drag to change values of variables.