distance (1,2,3),(4,6,3)
The distance is the norm of the difference of the points: the square root of the sum of the squared coordinate differences
Let's evaluate: ‖(4, 6, 3) -(1, 2, 3)‖
ⅰ (4, 6, 3) -(1, 2, 3) = (4 -1, 6 -2, 3 -3)
‖(4 -1, 6 -2, 3 -3)‖
ⓘ Start from 4 and move back 1 on the number line: 4 -1 = 3■Start from 6 and move back 2 on the number line: 6 -2 = 4■Start from 3 and move back 3 on the number line, down to zero: 3 -3 = 0
‖(3, 4, 0)‖
ⅰ ‖(3, 4, 0)‖ = 32 + 42 + 02
32 + 42 + 02
ⓘ Powers are computed before multiplications, additions and subtractions. An integer power is a repeated product: 32 = 3×3 = 9, 42 = 4×4 = 16■Adding 0 changes nothing: 42 + 0 = 42
9 + 16
ⓘ Parentheses are computed first: 9 + 16 = 25
25
ⓘ The square root of a number is the positive number whose square is that number: 25 = 5; 52 = 25
▶Distance:   5