Components can be decimals or fractions such as 1/2.
Keys: press U or V to pick a tip. Press [ or ] to step through the tips. Press an arrow key to move it one step (1). Hold Shift with an arrow key to move it five steps (5).
Separate components with commas. Fractions such as 1/2 are accepted.
Dot product
shadow of u on the line through v (a bar, no arrowhead)
u ⋅ v > 0u ⋅ v = 0u ⋅ v < 0
The dashed line through the origin is orthogonal to u. For every v on the same side of the line as u, the dot product is positive.