Question

find the distance between A(Cos theta,Sin theta) and B(sin theta,-cos theta)​

Answer 1

Hey friend, Here is your answer-
Let the co-ordinates of point A are (x1 , y1) and point B are (x2 , y2).

By using distance formula,
d (A , B) = under root (x2-x1) + (y2-y1)

=under root ( sin theta - cos theta) + ( - cos theta - sin theta )

Hope it will help you.

Answer 2

using distance formula

$\sqrt{(cos \alpha - \sin \alpha) {2 + ( \sin \alpha + \cos \alpha )2}^{?} }$

where 2 is square

$\sqrt{2}$