Trigonometry Flashcards
basic formulae & identities. target time per round: 30 sec
sin(−θ)
−sin θ
cos2A
cos2A–sin2A = 1–2sin2A = 2cos2A-1 = [(1-tan2A)/(1+tan2A)]
sin x – sin y
2 cos [(x+y)/2] sin [(x-y)/2]
cos(π/2-A)
sin A
sin(2π-A)
-sin A
sin(2π-A)
-sin A
sin x + sin y
= 2 sin [(x+y)/2] cos [(x-y)/2]
sin(π+A)
-sin A
cot(A-B)
= [(cot A cot B + 1)/(cot B – cot A)]
cos3A =
4cos3A – 3cosA
sin3A =
3sinA – 4sin3A
sin2A
2sinAcosA = [2tan A /(1+tan2A)]
cos x – cos y
-2 sin [(x+y)/2] sin [(x-y)/2]
tan 2A
(2 tan A)/(1-tan2A)
cos(−θ)
cos θ
cos(A+B)
cosAcosB - sinAsinB
2cosAsinB
sin(A+B) - sin(A-B)
tan(−θ)
−tan θ
cot(A+B)
[(cot A cot B − 1)/(cot B + cot A)]
sin(π/2-A)
cos A
tan3A =
[3tanA–tan3A]/[1−3tan2A]
cos(π-A)
-cos A
cos(A-B)
cosAcosB + sinAsinB
tan(A-B)
[(tan A – tan B)/(1 + tan A tan B)]
2sinAcosB
sin(A+B) + sin(A-B)
tan(A+B) =
[(tan A + tan B)/(1 – tan A tan B)]
cos(2π-A)
= cos A
sin(π-A)
sin A
-2sinAsinB
cos(A+B) - cos(A-B)
2sinAsinB
cos(A-B) - cos(A+B)
cos x + cos y
2 cos [(x+y)/2] cos [(x-y)/2]
cosec(−θ)
−cosecθ
