Evaluate the half angle in radians for sine

The video tutorial explains the use of half angle formulas in trigonometry, focusing on determining whether the sine of an angle is positive or negative based on its quadrant. It guides through calculating the value of U from U/2 and simplifying the trigonometric formula, emphasizing the importance of understanding the signs and simplification techniques.

Why is it important to determine the sign of the sine function when using half angle formulas?

• To simplify the calculation

• To ensure the angle is in the correct quadrant

• To decide whether to use the positive or negative root

• To convert the angle to radians

Which quadrant is the angle 3π/8 located in?

• First quadrant

• Second quadrant

• Third quadrant

• Fourth quadrant

What is the value of U if U/2 equals 3π/8?

• π

• π/2

• π/4

• 3π/4

What is the cosine of 3π/4?

• -1

• √2/2

• 1

• -√2/2

How can you simplify the expression 1 + √2/2 divided by 2?

• Subtract 2 from the denominator

• Multiply by 2 inside the radical

• Divide the numerator by 4

• Add 2 to the numerator