Trigonometric Cofunctions and Identities

This video tutorial focuses on cofunction identities in trigonometry, explaining the relationships between sine, cosine, tangent, cotangent, secant, and cosecant. It provides formulas and examples to illustrate how these identities work, such as sine theta equals cosine of 90 minus theta. The video also includes practice problems to help viewers apply these concepts and concludes with a summary of the key points discussed.

What is the cofunction identity for sine theta?

• cosine (90 - theta)

• cosecant (90 - theta)

• tangent (90 - theta)

• secant (90 - theta)

What is the cofunction identity for cosine theta?

• secant (90 - theta)

• sine (90 - theta)

• cosecant (90 - theta)

• tangent (90 - theta)

What is the cofunction identity for secant theta?

• cosecant (90 - theta)

• sine (90 - theta)

• cosine (90 - theta)

• tangent (90 - theta)

If sine 30 degrees equals cosine of which angle?

• 60 degrees

• 30 degrees

• 45 degrees

• 90 degrees

Sine 20 degrees is equal to cosine of what angle?

• 60 degrees

• 80 degrees

• 70 degrees

• 50 degrees

If sine 45 degrees equals cosine of which angle?

• 60 degrees

• 30 degrees

• 90 degrees

• 45 degrees

What is the cofunction of tangent 20 degrees?

• secant 70 degrees

• cosine 70 degrees

• sine 70 degrees

• cotangent 70 degrees

Cotangent pi/3 is equal to tangent of which angle in radians?

• pi/2

• pi/6

• pi/3

• pi/4

What is the cofunction of secant 42 degrees?

• cosine 48 degrees

• tangent 48 degrees

• cosecant 48 degrees

• sine 48 degrees

Cosine pi/8 is equal to sine of which angle in radians?

• 3pi/8

• pi/4

• pi/6

• pi/2