Pre-Calculus - Evaluating for the Double Angle of Sine with a Triangle

The video tutorial explains how to calculate the sine of 2U given that sine of U is -4/5. It introduces the formula for sine of 2U, which is 2 times sine of U times cosine of U. The tutorial then guides the viewer through determining the cosine of U by constructing a triangle in the correct quadrant, using the Pythagorean triple to find the missing side. Finally, it demonstrates how to plug the values into the formula to find the sine of 2U.

What is the formula for the sine of 2U?

• sine^2(U) - cosine^2(U)

• sine(U) + cosine(U)

• 2 * sine(U) * cosine(U)

• 2 * sine(U) + cosine(U)

In which quadrant should the triangle be constructed for angle U?

• Fourth quadrant

• Third quadrant

• Second quadrant

• First quadrant

What is the value of cosine(U) if sine(U) is -4/5?

• -3/5

• 4/5

• 3/5

• -4/5

Which mathematical concept helps in determining the missing side of the triangle?

• Trigonometric Identities

• Pythagorean Theorem

• Law of Sines

• Law of Cosines

What is the final result for sine(2U) given sine(U) = -4/5 and cosine(U) = -3/5?

• -12/25

• 12/25

• -24/25

• 24/25