TRIG IDENTITIES

Question 1

What is the small angle approximation for sin ⁡x?

Answer 1

X

Question 2

What is the small angle approximation for cos⁡ x?

Answer 2

1- (X^2/2)

Question 3

What is the small angle approximation for tan⁡ x?

Answer 3

X

Question 4

Sin(A+B)

Answer 4

sinAcosB + sinBcosA

Question 5

Cos(A+B)

Answer 5

cosAcosB - sinAsinB

Question 6

Tan(A+B)

Answer 6

tanA + tanB / 1-tanAtanB

Question 7

Sin(A-B)

Answer 7

sinAcosB - sinBcosA

Question 8

Cos(A-B)

Answer 8

cosAcosB + sinAsinB

Question 9

Tan(A-B)

Answer 9

tanA - tanB / 1+ tanAtanB

Question 10

Sin(2A)

Answer 10

2sinAcosA

Question 11

Cos(2A) - cos version

Answer 11

2cos^2A -1

Question 12

Cos(2A) - sin version

Answer 12

1 - 2sin^2A

Question 13

Cos(2A) - sin and cos version

Answer 13

cos^2A - sin^2A

Question 14

Tan(2A)

Answer 14

2tanA / 1 - tan^2A

Question 15

Cosec(x)

Answer 15

1/sinx

Question 16

Sec(x)

Answer 16

1/cosx

Question 17

Cot(x)

Answer 17

1/tanx

Question 18

Tan^2(x) +1

Answer 18

sec^2(x)

Question 19

Cot^2(x) +1

Answer 19

cosec^2(x)

Question 20

sin(x) / cos(x)

Answer 20

tan(x)

Question 21

cos(x) / sin(x)

Answer 21

cot(x)

Question 22

sin^2(x) + cos^2(x)

Answer 22

1

Question 23

What is the Sine rule used for finding a missing side?

Answer 23

a/sinA = b/sinB

Question 24

What is the Cosine rule used for finding a missing side?

Answer 24

a^2 = b^2 + c^2 - 2bcCosA

Question 25

What is the Cosine rule used for finding a missing side?

Answer 25

CosA = b^2 + c^2 - a^2 / 2bc

Question 25

What is the Sine rule used for finding a missing angle?

Answer 25

SinA/a = SinB/b

Question 25

What is Trig rule used to find the area of a triangle?

Answer 25

1/2 abSinC

Question 26

In radians, how do you find an arc length?

Answer 26

r0 (there’s no theta symbol on brainscape)

Question 27

In radians, how do you find the area of a sector?

Answer 27

1/2 r^2 0

Question 28

In radians, how do you find the area of a segment?

Answer 28

A = 1/2 r^2(0-sin0)