R-Flashcard Identities (Basic & Sum/Diff)

Front

What is the exact value of cos 105°?

Back

cos 105° = -√3/2

Front

What is the Pythagorean identity for sine and cosine?

Back

sin²(x) + cos²(x) = 1

Front

What is the cosecant function in terms of sine?

Back

csc(x) = 1/sin(x)

Front

How can you express cos(175°)cos(55°) + sin(175°)sin(55°) in terms of a single cosine function?

Back

cos(175°)cos(55°) + sin(175°)sin(55°) = cos(120°) (using the cosine addition formula).

Front

What is the simplified form of sec(θ) cot(θ) sin(θ)?

Back

sec(θ) cot(θ) sin(θ) = 1.

Front

What is the cosine of the sum of two angles formula?

Back

cos(A + B) = cos(A)cos(B) - sin(A)sin(B).

Front

What is the sine of the difference of two angles formula?

Back

sin(A - B) = sin(A)cos(B) - cos(A)sin(B).

Front

What is the tangent of an angle in terms of sine and cosine?

Back

tan(x) = sin(x)/cos(x).

Front

What is the relationship between secant and cosine?

Back

sec(x) = 1/cos(x).

Front

What is the relationship between cotangent and sine/cosine?

Back

cot(x) = cos(x)/sin(x).