Question

(1+sinA)2 -(1-sinA)2=4sinA

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Answer 1

Expand the binomials.

`(x+y)^2 - (x-y)^2 = (x^2 + 2xy + y^2) - (x^2 - 2xy + y^2) = 4xy`

Now let
`x=1` and
`y=\sin(A)`.