plz help:)



Your use of parentheses is not standard, so I made a guess as to the equation in this exercise.

1 - 2*sin(x)^2 + sin(4x) = 3*cos(x)^2 - 3*sin(x)^2

No, this is not an identity.

Look at two of the double-angle identities for cosine:

cos(x)^2 - sin(x)^2 = cos(2x)

1 - 2*sin(x)^2 = cos(2x)

What do you get, after making these two substitutions in your equation and simplifying?

 
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