Evaluate the half angle for cosine from a triangle

The video tutorial explains the cosine formula and its application using triangles and constraints. It discusses how to determine the cosine value based on the quadrant and provides methods to simplify the expression. The tutorial emphasizes algebraic manipulation and rationalization of denominators to achieve a simplified form.

What is the formula for cosine in terms of Theta?

• cosine of Theta all over 2

• 1 + sine of Theta all over 2

• 1 + cosine of Theta all over 2

• 1 - cosine of Theta all over 2

In which quadrant is cosine negative?

• First quadrant

• Second quadrant

• Third quadrant

• Fourth quadrant

What is the first step in simplifying the expression 1 + cosine(-3/5) all divided by 2?

• Add 3 to both sides

• Multiply the top and bottom by 5

• Combine the fractions

• Multiply the top and bottom by 3

What is the simplified form of sqrt 2 / sqrt 10?

• sqrt 20 / 10

• sqrt 10 / 2

• sqrt 2 / 5

• sqrt 5 / 5

What is the final simplified form of the expression discussed in the video?

• - sqrt 5 / 5

• sqrt 10 / 10

• sqrt 5 / 5

• - sqrt 10 / 10