Pre-Calculus - Using the Double Angle Formula to Evaluate for Cosine of an Angle and Triangle

The video tutorial covers solving trigonometric problems by creating triangles for angles not on the unit circle. It explains the use of Pythagorean triples to simplify calculations and demonstrates evaluating cosine using various methods. The tutorial emphasizes understanding constraints and applying formulas effectively.

What is the first step when dealing with angles not on the unit circle?

• Use the unit circle directly

• Create a triangle

• Apply the sine rule

• Use a calculator

What is the tangent of angle U in the example provided?

• 5/3

• 3/4

• 4/3

• 3/5

What is the hypotenuse of the triangle in the example, given that tangent U = 3/4?

• 3

• 6

• 4

• 5

Which formula is used to evaluate the cosine of two times an angle?

• cosine squared of U - 1

• 2 * sine squared of U - 1

• 2 * cosine squared of U - 1

• sine squared of U + 1

What is the final result of the cosine evaluation in the example?

• 7/25

• 25/32

• 16/25

• 32/25