Trigonometric Identities QuizOnline version Test your trig identities by Noor Alzoubi 1 Which identity expresses sin^2(x) + cos^2(x) = 1 in terms of tan(x)? a cos^2(x) = 1 - sin^2(x) b 1 + tan^2(x) = sec^2(x) c sin(2x) = 2sin(x)cos(x) d sec^2(x) = 1 + cot^2(x) 2 What is the double-angle formula for cosine? a cos(2x) = sin^2(x) − cos^2(x) b cos(2x) = cos^2(x) − sin^2(x) c cos(2x) = 1 − tan^2(x) d cos(2x) = 2sin(x)cos(x) 3 Which identity gives sin(2x) in terms of sin and cos? a tan(2x) = 2tan(x) b cos(2x) = 2cos^2(x) − 1 c sin(2x) = sin^2(x) + cos^2(x) d sin(2x) = 2sin(x)cos(x) 4 What is the Pythagorean identity for sec^2(x) in terms of tan(x)? a sec^2(x) = cos^2(x) b sec^2(x) = 1 − tan^2(x) c sec^2(x) = 1 + tan^2(x) d sec^2(x) = cot^2(x) + 1 5 Which is a valid reciprocal identity? a sin(x) = 1/csc(x) b sin(x) = sec(x) c tan(x) = cot(x) d cos(x) = tan(x) 6 Which identity converts tan(x) in terms of sin and cos? a tan(x) = sin^2(x) b tan(x) = cos(x)/sin(x) c tan(x) = 1 − cos^2(x) d tan(x) = sin(x)/cos(x) 7 What is the double-angle formula for sine? a sin(2x) = 1 − cos(2x) b sin(2x) = sin^2(x) + cos^2(x) c sin(2x) = 2sin(x)cos(x) d sin(2x) = 2cos^2(x) 8 Which identity simplifies sin^2(x) to 1 − cos^2(x)? a cos^2(x) = 1 − sin^2(x) b sin(2x) = 2sin(x)cos(x) c sin^2(x) = 1 − cos^2(x) d tan^2(x) = sin^2(x) 9 What is the identity for cos(2x) using sin^2 and cos^2? a cos(2x) = cos^2(x) − sin^2(x) b cos(2x) = sin^2(x) − cos^2(x) c cos(2x) = 1 − tan^2(x) d cos(2x) = 2sin^2(x) − 1 10 Which identity expresses tan^2(x) in terms of sec^2(x)? a tan^2(x) = 1 − sec^2(x) b tan^2(x) = sec^2(x) − 1 c tan^2(x) = sin^2(x) d tan^2(x) = cos^2(x)
