Trigonometric Functions and Identities

The video tutorial explains how to find the sine of an angle located in the fourth quadrant, given the cosine value. It uses the Pythagorean identity to substitute and simplify the equation, eventually solving for sine. The tutorial also discusses determining the sign of sine based on the quadrant location, emphasizing that sine is negative in the fourth quadrant.

In which quadrant is the angle theta located?

• First Quadrant

• Second Quadrant

• Third Quadrant

• Fourth Quadrant

What is the given value of cosine of theta?

• 10/19

• 9/10

• 19/9

• 9/19

Which identity is used to find the sine of theta?

• Sine-Cosine Identity

• Pythagorean Identity

• Tangent Identity

• Reciprocal Identity

What is the result of squaring 9/19?

• 81/19

• 9/361

• 9/19

• 81/361

What is the common denominator used to simplify the expression?

• 81

• 19

• 280

• 361

What is the simplified form of sine squared theta?

• 81/361

• 280/361

• 280/19

• 19/361

What is the square root of 361?

• 18

• 19

• 20

• 21

What is the simplified form of sine of theta?

• √70/18

• 2√70/18

• √70/19

• 2√70/19

In the fourth quadrant, what is the sign of sine?

• Undefined

• Zero

• Negative

• Positive

Why is the sine value negative in the fourth quadrant?

• Because both sine and cosine are positive

• Because it is above the x-axis

• Because it is below the x-axis

• Because cosine is negative