TRIG IDENTITIES Flashcards
What is the small angle approximation for sin x?
X
What is the small angle approximation for cos x?
1- (X^2/2)
What is the small angle approximation for tan x?
X
Sin(A+B)
sinAcosB + sinBcosA
Cos(A+B)
cosAcosB - sinAsinB
Tan(A+B)
tanA + tanB / 1-tanAtanB
Sin(A-B)
sinAcosB - sinBcosA
Cos(A-B)
cosAcosB + sinAsinB
Tan(A-B)
tanA - tanB / 1+ tanAtanB
Sin(2A)
2sinAcosA
Cos(2A) - cos version
2cos^2A -1
Cos(2A) - sin version
1 - 2sin^2A
Cos(2A) - sin and cos version
cos^2A - sin^2A
Tan(2A)
2tanA / 1 - tan^2A
Cosec(x)
1/sinx
Sec(x)
1/cosx
Cot(x)
1/tanx
Tan^2(x) +1
sec^2(x)
Cot^2(x) +1
cosec^2(x)
sin(x) / cos(x)
tan(x)
cos(x) / sin(x)
cot(x)
sin^2(x) + cos^2(x)
1
What is the Sine rule used for finding a missing side?
a/sinA = b/sinB
What is the Cosine rule used for finding a missing side?
a^2 = b^2 + c^2 - 2bcCosA
What is the Cosine rule used for finding a missing side?
CosA = b^2 + c^2 - a^2 / 2bc
What is the Sine rule used for finding a missing angle?
SinA/a = SinB/b
What is Trig rule used to find the area of a triangle?
1/2 abSinC
In radians, how do you find an arc length?
r0 (there’s no theta symbol on brainscape)
In radians, how do you find the area of a sector?
1/2 r^2 0
In radians, how do you find the area of a segment?
A = 1/2 r^2(0-sin0)
