Trigonometry

Question 1

How do we use trigonometry to find missing sides on right angled triangles?

Answer 1

SOH CAH TOA

Question 2

How do you use trigonometry to find missing angles?

Answer 2

Inverse of trigonometric functions eg. Sin to the -1

Question 3

How do you find the area of non right angled triangles?

Answer 3

1/2 ab sinC
Angle between 2 sides

Question 4

Sine rule for lengths:

Answer 4

a b
—— = ——
SinA SinB

Question 5

When do we use the sine rule?

Answer 5

Opposites
Angle opposite side length

Question 6

Sin rule for angles

Answer 6

SinA. SinB
——- = ———-
a. b

Question 7

Cosine rule for lengths

Answer 7

a2=b2 + c*2 - (2 x bc cosA)

Question 8

Cosine rule for angles

Answer 8

CosA = b2+c2 - a*2
———————
2bc

Question 9

When do we use the cosine rule?

Answer 9

When we have 2 sides and an angle between them

Question 10

Pythagoras theorem

Answer 10

a2 = b2 +c*2

Question 11

Exact angle: sin30

Answer 11

1
—
2

Question 12

Exact angle: cos30

Answer 12

Square root of 3
————————-
2

Question 13

Exact angle: tan30

Answer 13

1
—
2

Question 14

Exact angle: sin45

Answer 14

1
——
Square root of 2

Question 15

Exact angle: cos45

Answer 15

1
——
Square root of 2

Question 16

Exact angle: tan45

Answer 16

1

Question 17

Exact angle: sin60

Answer 17

Square root of 3
—- —- - ————-
2

Question 18

Exact angle: cos60

Answer 18

1
—
2

Question 19

Exact angle: tan60

Answer 19

Square root of 3
————————
1