Answer :

HomertheGenius
         cos 2 x = cos² x - sin² x = 1 - sin² x - sin² x = 1 - 2 sin² x.
         Answer: A ) 1 - sin² x and D ) cos² x - sin² x 
         Thank you.
abidemiokin

The correct expansion for cos2x are cos²x - sin²x and 1 - 2sin²x

Trigonometry identity

Trigonometry identity are expressed as sine, cosine and tangent function. Given the double angle;

Cos2x = Cos(x+x)

Cos(x+x) = cosxcosx - sinxsinx

Cos(x+x) =cos²x - sin²x

Since cos²x = 1 - sin²x, then;

Cos(x+x) =1 - sin²x- sin²x

Cos2x = 1 - 2sin²x

Hence the correct expansion for cos2x are cos²x - sin²x and 1 - 2sin²x

Learn more on trig function here: https://brainly.com/question/1143565

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