Pre-Calculus - Learn how to simplify a trigonometric expression using cofunction identities

The video tutorial covers the concept of cofunction identities in trigonometry, focusing on the relationship between cosine and sine. It explains how the cosine of an angle subtracted from 90 degrees is equal to the sine of that angle, using both degree and radian measures. The tutorial further simplifies trigonometric expressions by transforming secant into a reciprocal identity and ultimately deriving the tangent function. The session concludes with a review of these key concepts, emphasizing the equivalence of angles in different units.

What is the relationship between cosine of π/2 minus an angle and sine of that angle?

• They are unrelated.

• They are equal.

• Sine is half of the cosine.

• Cosine is double the sine.

How can secant be expressed using reciprocal identities?

• As one over sine.

• As cosine over sine.

• As one over cosine.

• As sine over cosine.

What trigonometric identity is formed by the ratio of sine over cosine?

• Tangent

• Cotangent

• Secant

• Cosecant

How is π/2 related to 90 degrees?

• They are unrelated.

• π/2 is half of 90 degrees.

• 90 degrees is double π/2.

• They are the same angle in different units.

What is the cofunction identity for cosine of 90 degrees minus an angle?

• It equals the cotangent of the angle.

• It equals the secant of the angle.

• It equals the sine of the angle.

• It equals the tangent of the angle.