Learn how to find the sine of 5 pi over 4 without a calculator

The video tutorial explains the concept of angles in a circle, focusing on reference angles and their significance in trigonometry. It covers how to calculate the sine of a reference angle, specifically π/4, and discusses the importance of understanding which quadrant an angle lies in to determine the sign of trigonometric functions. The tutorial emphasizes the need to memorize key angles and their trigonometric values for quick calculations.

What is the reference angle for 5π/4?

• π/2

• π/4

• 3π/4

• π

What is the sine of π/4?

• √3/2

• 1

• √2/2

• 1/2

In which quadrant is the sine of an angle negative?

• Fourth

• First

• Second

• Third

What is the tangent of 5π/4?

• -1

• 1

• Undefined

• 0

Which trigonometric function is positive in the third quadrant?

• Tangent

• Cosine

• Sine

• Cosecant