Выражение: sin^[email protected]+sin^[email protected] * cos^[email protected]+ cos^[email protected]

Sin⁴α + sin² α *cos² α + cos²α = 
= (sin⁴α + sin² α *cos² α) + cos²α = 
= sin²α * (sin²α + cos³α) + cos²α = 
= sin²α * 1 + cos²α = 
= sin²α + cos³α = 1