Simplify the following expressions: 1) 4cos³ 3α + 4sin³ 3α; 3) 1 - sin² 3x; 5) sin² 7y - 1; 7) 2sin² x - 1

Simplify the following expressions:

1. \( 4\cos^3 3\alpha + 4\sin^3 3\alpha \)
2. \( 2\sin^2 5\alpha + 2\cos^2 5\alpha \)
3. \( 1 - \sin^2 3x = \cos^2 3x \)
4. \( 1 - \cos^2 4\beta = \sin^2 4\beta \)
5. \( \sin^2 7y - 1 = - (1 - \sin^2 7y) = -\cos^2 7y \)
6. \( \cos^2 3t - 1 = - (1 - \cos^2 3t) = -\sin^2 3t \)
7. \( 2\sin^2 x - 1 = - (1 - 2\sin^2 x) = -\cos(2x) \)