Top

Discussion

What is the value of \(\sin 15°\)?

  • A.\(\frac{\sqrt{3}+1}{2\sqrt{2}}\)
  • B.\(\frac{\sqrt{3}-1}{2\sqrt{2}}\)
  • C.\(\frac{\sqrt{3}}{2}\)
  • D.\(\frac{1}{2}\)

Answer: B

We can write 15° as the difference of two standard angles, 45° - 30°.

Using the sine subtraction formula: \(\sin(A-B) = \sin A \cos B - \cos A \sin B\).

\(\sin(45°-30°) = \sin 45° \cos 30° - \cos 45° \sin 30°\)

= \((\frac{1}{\sqrt{2}})(\frac{\sqrt{3}}{2}) - (\frac{1}{\sqrt{2}})(\frac{1}{2})\)

= \(\frac{\sqrt{3}}{2\sqrt{2}} - \frac{1}{2\sqrt{2}} = \frac{\sqrt{3}-1}{2\sqrt{2}}\).

No comment is present. Be the first to comment.
Loading…

Post your comment