Calculating Trigonometric Values with Hand Trick

In this video, Lucy demonstrates a hand trick to easily find exact trigonometric values for angles 0°, 30°, 45°, 60°, and 90°. By associating each finger with an angle and using a simple method of counting fingers, viewers can calculate sine, cosine, and tangent values without memorizing a table. The technique involves bending a finger corresponding to the angle and counting the fingers above or below it, applying square roots and division to find the desired trigonometric value.

What angles are used in the hand trick method for finding trigonometric values?

• 0, 15, 30, 45, 60

• 0, 30, 45, 60, 90

• 15, 30, 45, 60, 75

• 30, 45, 60, 75, 90

How do you calculate sin 30° using the hand trick?

• Square root of 2 divided by 2

• Square root of 1 divided by 2

• Square root of 3 divided by 2

• Square root of 4 divided by 2

What is the sine value of 90° using the hand trick?

• √3/2

• 1/2

• 0

• 1

How do you calculate cos 60° using the hand trick?

• Square root of 1 divided by 2

• Square root of 2 divided by 2

• Square root of 3 divided by 2

• Square root of 4 divided by 2

What is the cosine value of 90° using the hand trick?

• √3/2

• 1

• 1/2

• 0

How do you calculate tan 60° using the hand trick?

• 0

• 1

• 1/√3

• √3

What is the tangent value of 30° using the hand trick?

• √3

• 1/√3

• 0

• 1

What is the key step for calculating tangent values using the hand trick?

• Use only the thumb

• Count fingers below the bent finger

• Count fingers above the bent finger

• Flip the hand and compare fingers

What is the general rule for calculating sine values using the hand trick?

• Root fingers above divided by two

• Root fingers below divided by two

• Root fingers above divided by root fingers

• Root fingers below divided by root fingers

What is the general rule for calculating cosine values using the hand trick?

• Root fingers below divided by two

• Root fingers above divided by two

• Root fingers above divided by root fingers

• Root fingers below divided by root fingers