Identies

Question 0

How else can you write CotX?

Answer 0

1/tanX

Question 1

What are the two identities from C2

Answer 1

1) Sin²x + Cos²x = 1 (This can be rearranged)
2) SinX / CosX

Question 2

How else can you write Sec?

Answer 2

1/cosX

Question 3

How elese can you write Cosec?

Answer 3

1/sinX

Question 4

What is the relationship between Tan²X and Sec²X?

Answer 4

Tan²X + 1 = Sec²X = Sec²X

Question 5

What is the relationship between CotX and CosecX?

Answer 5

1 + Cot²X = Cosec²X

Question 6

Between 0^°-90^°what angles are positive?

Answer 6

All positive

Question 7

What angles are positive between 90^°-180^°?

Answer 7

SinX

Question 8

What angles are positive between 180°-270°?

Answer 8

TanX

Question 9

What angles are positive between 270°-360°?

Answer 9

CosX

Question 10

The Addition Formulee:

Sin(a + b)

Sin(a - b)

Answer 10

1) SinACosB + CosASinB
2) SinACosB - CosASinB

Question 11

The Addition Formulee:

1) Cos(A + B)
2) Cos(A - B)

Answer 11

1) CosACosB - SinASinB
2) CosAcosB + SinAsinB

Question 12

The Addition Formulee:

1) Tan(A + B)
2) Tan(A - B)

Answer 12

1) TanA + TanB / 1 - TanATanB
2) TanA - TanB / 1 + TanATanB

Question 13

Double angle formula:

1) Sin2A
2) Cos2A
3) Tan2A

Answer 13

1) 2SinACosA
2) Cos²A - Sin²A
3) 2TanA/ 1 - Tan²A

Question 14

What does 1 link nicely with?

Answer 14

Cos(2A) - The double angle formule

Cos(2A)= Cos²A- Cos²A. From this we can get:

1) Cos(2A)= 2Cos²A - 1

This gives: 2Cos²A = 1 + Cos(2A)

2) Cos(2A) = 1 - 2Sin²A

This gives: 2Sin²A = 1 - Cos(2A)