(sin²)³+(cos²)³= (sin²+cos²)(sin⁴-sin²cos²+cos²)= sin⁴+cos⁴-sin²cos²=(sin²)²+(cos²)²-sin²cos²[a²+b²=(a+b)²-2ab]= (sin²+cos²)² -2sin²cos²-sin²cos²= (1)²-3sin²cos² = 1 - 3sin²cos²
Your experience on this site will be improved by allowing cookies. Read Cookie Policy