Topic 5

Question 1

What is sin(2A)

Answer 1

2(sinAcosA)

Question 2

What is cos(2A)

Answer 2

cos^2(A)-sin^2(A)

Question 3

What is the other two variants if cos(2A)

Answer 3

2cos^2A-1
1-2sin^2A

Question 4

sin(A+B)

Answer 4

sinAcosB+cosAsinB

Question 5

sin(A-B)

Answer 5

sinAcosB-cosAsinB

Question 6

cos(A+B)

Answer 6

cosAcosB-sinAsinB

Question 7

cos(A-B)

Answer 7

cosAcosB+sinAsinB

Question 8

tan(A+B)

Answer 8

(tanA+tanB)/1-tanAtanB

Question 9

tan(A-B)

Answer 9

(tanA-tanB)/1+tanAtanB

Question 10

What is tan(2A)

Answer 10

(2tanA)/1-tan^2A

Question 11

Identity with sin^2 and cos^2

Answer 11

sin^2x + cos^2x = 1

Question 12

Identity with tan^2x and sec^2x

Answer 12

tan^2x + 1 = sec^2x

Question 13

Identity with cot^2x cosec^2x

Answer 13

1 + cot^2x = cosec^2x

Question 14

What is the small angle approximation for cos θ

Answer 14

1 - (θ^2)/2

Question 15

What is the small angle approximation for sin θ

Answer 15

θ

Question 16

What is the small angle approximation for tan θ

Answer 16

θ

Question 17

What are the conditions for small angle approximation

Answer 17

The angle must be small
The angle must be in radians

Question 18

What is cosecant x

Answer 18

1/sin x

Question 19

What is secant x

Answer 19

1/cos x

Question 20

What is cotangent x

Answer 20

1/tan x

Question 21

What is arcsin x

Answer 21

sin^-1 x

Question 22

What is arcos x

Answer 22

cos^-1 x

Question 23

What is arctan x

Answer 23

tan^-1 x