The discussion addresses the absence of negative square roots in half angle formulas for sine and cosine, clarifying that these formulas are derived from the properties of trigonometric functions, which are defined for real values. It emphasizes that sine and cosine values range from -1 to 1, ensuring that the square roots involved in the half angle formulas yield non-negative results. The conversation highlights the importance of understanding the range of trigonometric functions when applying these formulas. Overall, the half angle formulas remain valid without concern for negative square roots due to the defined range of sine and cosine. This understanding is crucial for correctly applying these formulas in mathematical problems.