What is cos15 degrees?

Answer 1

The cosine of 15 degrees can be calculated using the cosine subtraction formula: (\cos(15^\circ) = \cos(45^\circ - 30^\circ)). This gives us (\cos(15^\circ) = \cos(45^\circ)\cos(30^\circ) + \sin(45^\circ)\sin(30^\circ). Substituting the known values, (\cos(45^\circ) = \frac{\sqrt{2}}{2}), (\cos(30^\circ) = \frac{\sqrt{3}}{2}), (\sin(45^\circ) = \frac{\sqrt{2}}{2}), and (\sin(30^\circ) = \frac{1}{2}), we find that (\cos(15^\circ) = \frac{\sqrt{6} + \sqrt{2}}{4}).