Write and evaluate expression using sum and difference identities

The video tutorial explains how to solve a trigonometric expression without using a calculator. The teacher guides students through recognizing and applying the sine formula for the difference of two angles. By identifying the relationship in the expression, the teacher demonstrates how to simplify and solve it, emphasizing the sine of 90 degrees equals 1.

What is the main challenge mentioned by the teacher when evaluating trigonometric functions without a calculator?

• Confusion with algebraic expressions

• Difficulty in calculating exact values

• Inability to recognize angles

• Lack of understanding of trigonometric identities

Which trigonometric formula does the teacher identify in the expression?

• Sine formula

• Secant formula

• Cosine formula

• Tangent formula

What type of angle operation is identified in the sine formula?

• Sum of two angles

• Difference of two angles

• Product of two angles

• Division of two angles

What is the sine of 90 degrees as concluded by the teacher?

• 0

• 0.5

• Undefined

• 1

What mathematical operation does the teacher emphasize cannot be distributed in the given problem?

• Subtraction

• Addition

• Division

• Multiplication