Which of the following is/are identity/identities? 1. (sin³θ + cos³θ)/(sinθ + cosθ) + sinθ cosθ = 1; 0 < θ < π/2. 2. 1 − sin⁶θ = cos²θ(cos⁴θ + 3sin²θ).

1: (sin³+cos³)/(sin+cos) = sin²−sincos+cos² = 1−sincos. Adding sincos = 1. ✓. 2: 1−sin⁶ = (1−sin²)(1+sin²+sin⁴) = cos²(1+sin²+sin⁴). Need 1+sin²+sin⁴ = cos⁴+3sin². cos⁴ = (1−sin²)² = 1−2sin²+sin⁴. cos⁴+3sin² = 1+sin²+sin⁴. ✓. Both correct.