Can someone help me with this please? I've done it, but I'm not sure whether the answer is right.
The question is

Given A is reflex and cos A = 1/5, find sin2A.

This is my working..
sin A = -sqrt24 / 5
sin2A= 2sinAcosA
= 2 x (-sqrt24 / 5) x (1/5)
= -2 sqrt24 / 25

Can someone tell me whether my working and answer is wrong or right? And if it's wrong please tell and show me why..Thank you so much!
A is reflex means the angle A is more than 180 degrees