Trigonometric Functions and Quadrants

Amal Kumar presents a video tutorial for Ellen, focusing on equivalent trigonometric functions. He cautions that teachers often provide different questions, though they may be similar. The video reviews trigonometric ratios, specifically cosine and sine functions, and explains how to determine equivalent angles and values. Amal provides examples and a test question, encouraging viewers to explore additional resources for better understanding and test preparation.

What is the main caution given by the teacher regarding test questions?

• Questions are always harder than expected.

• Teachers often give different but similar questions.

• The book questions are never used in tests.

• All questions are the same as in the book.

Why is it important to understand equivalent trigonometric functions?

• To solve only sine functions.

• To memorize all possible angles.

• To ignore quadrant rules.

• To avoid mistakes by relating angles to acute angles.

What is the acute angle for cos(13π/10)?

• 13π/10

• π/10

• π/2

• 3π/10

In which quadrant is cos(13π/10) located?

• Third quadrant

• Second quadrant

• First quadrant

• Fourth quadrant

What is the sign of cos(13π/10) in its quadrant?

• Negative

• Zero

• Positive

• Undefined

What is the result of simplifying cos(13π/10) using quadrant rules?

• Negative sine function

• Positive cosine function

• Negative cosine function

• Positive sine function

What is the acute angle for cos(13π/10)?

• 3π/10

• 13π/10

• π/2

• π/10

In which quadrant is cos(13π/10) located?

• First quadrant

• Second quadrant

• Third quadrant

• Fourth quadrant

What is the sign of cos(13π/10) in its quadrant?

• Undefined

• Negative

• Positive

• Zero

How is -sin(13π/7) simplified using quadrant rules?

• As a negative sine function

• As a positive sine function

• As a negative cosine function

• As a positive cosine function