Question

find the distance between the points (cos, sin) and (sin, -cos)​

Answer 1

by distance formula

$\sqrt{(sin-cos)^{2}+(sin +cos)^{2} } \\=\sqrt{sin^{2} +cos^{2}-2sincos+sin^{2}+cos^{2}+2sincos } \\=\sqrt{1+1} \\=\sqrt{2}$