Question

sin4x+cos4x=1-2sin2xcos2x

Answer 1

LHS- sin4x + cos4x

= (sin2x)2 + (cos2x)2

= (sin2x + cos2x)2 - 2sin2xcos2x  {since a2 +b2 = (a+b)2 - 2ab}

= 12 - 2sin2xcos2x {since sin2x +cos2x = 1}

= 1 - 2sin2xcos2x

= RHS


hope helpful for u

Answer 2

Hey !!!

Sin⁴x + cos⁴x

=( Sin²x)² +( cos²x)²

•°• a² + b² = (a + b)² - 2ab
Like that .

=( Sin²x + cos²x )² - 2sin²x cos²x

= 1² - 2sin²x cos²x

= 1 - 2sin²x cos²x

Hope it helps you !!!

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