(x^3)^2 - (x*y^2)^2 =
= (x^3 - xy^2)(x^3 + xy^2)
==========================
1) Y^3 * V 4Y^2 = Y^3 * 2Y = 2Y^4
2) 7A * V ( 16 \ A^2) = 7A * 4 \ A = 7A * 4A^(-1) = 28 A^ ( 1 - 1) = 28 A^0 = 28
cosx cos2x cos4x cos8x cos16x cos32x =
= (2sinxcosx / 2sinx) cos2x cos4x cos8x cos16x cos32x =
= (sin2x / 2sinx) cos2x cos4x cos8x cos16x cos32x =
= (sin2x / 2sinx) (2sin2xcos2x / 2sin2x) cos4x cos8x cos16x cos32x =
= (sin4x / 4sinx) (2sin4xcos4x / 2sin4x) cos8x cos16x cos32x =
= (sin8x / 8sinx) (2sin8xcos8x / 2sin8x) cos16x cos32x =
= (sin16x / 16sinx) (2sin16xcos16x / 2sin16x) cos32x =
= (sin32x / 32sinx) (2sin32xcos32x / 2sin32x) =
= sin64x / 64sinx
x = π/9