Evaluate using the Sum and Difference Formulas

The video tutorial covers the cosine addition formula, demonstrating how to apply it to specific angles. The instructor explains the calculations for cosine and sine in different quadrants and discusses factoring techniques in trigonometric expressions. The session concludes with a reflection on teaching methods and approaches to help students understand the material better.

What is the formula for the cosine of the sum of two angles?

• cos(U + V) = cos(U)cos(V) - sin(U)sin(V)

• cos(U + V) = sin(U)sin(V) + cos(U)cos(V)

• cos(U + V) = sin(U)cos(V) + cos(U)sin(V)

• cos(U + V) = cos(U)sin(V) - sin(U)cos(V)

In which quadrant is the cosine of 120 degrees negative?

• First quadrant

• Fourth quadrant

• Third quadrant

• Second quadrant

What is the value of cosine 45 degrees?

• 1

• sqrt(3)/2

• sqrt(2)/2

• 0

When factoring an expression, what should you look for?

• The largest number

• The smallest number

• The highest power

• Common terms

Why is it important to factor out common terms in an expression?

• To increase the complexity

• To change the expression completely

• To simplify the expression

• To make the expression longer