What is the distance between the points $$P(m\cos 2\alpha ,m\sin 2\alpha )$$ and $$Q(m\cos 2\beta ,m\sin 2\beta )$$ ?

An equilateral triangle has one vertex at ($$-$$1, $$-$$1) and another vertex at $$( - \sqrt 3 ,\sqrt 3 )$$. The third vertex may lie on

The equation ax + by + c = 0 represents a straight line

What is the angle between the lines x cos$$\alpha$$ + y sin$$\alpha$$ = a and x sin$$\beta$$ $$-$$ y cos$$\beta$$ = a ?