sin(-2A)=-2sinAcos(-A)
sin(-2A)=-2sinAcos(-A)
First, start by proving
sin (x + y) = sin(x) cos(y) + cos(x) sin (y)
sin(x+y) and cos(x+y)
Then simplify by letting x = y to the traditional double-angle formula:
Finally, substitute -A for x and you'll have your proof.
Hi how you solved?:confused:
Thanks
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