Finding the exact value for sine of 15 degrees using the half angle formula

The video tutorial covers the use of sum, difference, and half-angle formulas in trigonometry. It explains how to determine the sign of sine based on the quadrant and solve for angles using these formulas. The tutorial concludes with a detailed calculation to find the exact answer, emphasizing the application of radicals and the unit circle.

Which of the following formulas is used to find the sine of half an angle?

• Sine of U/2 = ±√(1 - cosine(U))/2

• Sine of U = 2 * sine(U/2) * cosine(U/2)

• Sine of U = cosine(U/2) * sine(U/2)

• Sine of U/2 = 1 - cosine(U)

In which quadrant is the sine of 15 degrees positive?

• Fourth quadrant

• First quadrant

• Third quadrant

• Second quadrant

What is the value of U if U/2 equals 15 degrees?

• 45 degrees

• 60 degrees

• 30 degrees

• 90 degrees

What is the cosine of 30 degrees according to the unit circle?

• 1

• √2/2

• √3/2

• 1/2

How do you simplify the expression √(2 - √3)/4?

• √2 - √3

• √(2 - √3)/2

• √2 + √3

• √(2 - √3)/4