Question

calcular a distância entre os pontos A (4,-1) e B (2,1)

Answer 1

vamos usar:

dab² = ( xb-xa)² + ( yb-ya)²
dab² = ( 2-4)² + (1+1)²

dab= √(4+4)

dab = 2√2

Answer 2

Basta usar a fórmula de distância ... 

$D= \sqrt{(xb-xa)^{2}+(yb-ya)^{2}} \\\\\\\\D= \sqrt{(2-4)^{2}+(1-(-1))^{2}} \\\\\\\\D= \sqrt{(-2)^{2}+(1+1)^{2}} \\\\\\\\D= \sqrt{4+2^{2}} \\\\\\\\D= \sqrt{4+4} \\\\\\\\D= \sqrt{8} \\\\\\\\D= \sqrt{4.2} \\\\\\\\D= \sqrt{2^{2}.2} \\\\\\\\\boxed{\bosed{D=2 \sqrt{2} }}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ok$