Which of the following expressions has the same value as cos 30° ? (1 point) sin 30° cos 60° cos π /6 sin π /6

1 answer

To find which expression has the same value as \(\cos 30^\circ\), we first calculate \(\cos 30^\circ\):

\[ \cos 30^\circ = \frac{\sqrt{3}}{2} \]

Now, we check each of the given expressions.

  1. sin 30° cos 60°:

    • \(\sin 30^\circ = \frac{1}{2}\)
    • \(\cos 60^\circ = \frac{1}{2}\)
    • Therefore, \(\sin 30^\circ \cos 60^\circ = \frac{1}{2} \times \frac{1}{2} = \frac{1}{4}\)
  2. cos \(\frac{\pi}{6}\):

    • \(\cos \frac{\pi}{6} = \cos 30^\circ = \frac{\sqrt{3}}{2}\)
  3. sin \(\frac{\pi}{6}\):

    • \(\sin \frac{\pi}{6} = \frac{1}{2}\)

Now check sin \(\frac{\pi}{6}\) cos \(\frac{\pi}{6}\): \[ \sin \frac{\pi}{6} \cos \frac{\pi}{6} = \frac{1}{2} \times \frac{\sqrt{3}}{2} = \frac{\sqrt{3}}{4} \]

After evaluating the expressions, we see that:

  • \(\sin 30^\circ \cos 60^\circ = \frac{1}{4}\)
  • \(\cos \frac{\pi}{6} = \frac{\sqrt{3}}{2}\)
  • \(\sin \frac{\pi}{6} \cos \frac{\pi}{6} = \frac{\sqrt{3}}{4}\)

The only expression that has the same value as \(\cos 30^\circ\) is

cos \(\frac{\pi}{6}\), which is equal to \(\frac{\sqrt{3}}{2}\).