How to evaluate for the half angle of cosine

What is the purpose of using the half-angle formula in this context?

• To find the sine of 75 degrees

• To evaluate the cosine of 75 degrees

• To determine the tangent of 75 degrees

• To calculate the secant of 75 degrees

What is the value of U when using the half-angle formula for cosine of 75 degrees?

• 90 degrees

• 150 degrees

• 45 degrees

• 75 degrees

Which point on the unit circle corresponds to 150 degrees?

• (-√3/2, 1/2)

• (√3/2, -1/2)

• (1/2, √3/2)

• (-1/2, -√3/2)

What operation is performed to eliminate fractions in the expression?

• Adding the numerator and denominator

• Subtracting the numerator from the denominator

• Multiplying by the denominator

• Dividing by the numerator

What is the final simplified form of the expression for cosine of 75 degrees?

• ±1/4(2 - √3)

• ±1/4(2 + √3)

• ±1/2(2 - √3)

• ±1/2(2 + √3)