Explanation:
∴ cos 105° = cos(1.8325) = -(√6-√2)/4 or -0.2588190. . . Explanation: For cos 105 degrees, the angle 105° lies between 90° and 180° (Second Quadrant). Since cosine function is negative in the second quadrant, thus cos 105° value = -(√6-√2)/4 or -0.2588190