Trigonometry Flashcards
1
Q
sin rule (use when given 2 angles and a side)
A
a/ b/ c/
sin A = sin B= sinC
2
Q
cos rule (use when 3 sides are given)
A
cos A = (a²-b²-c²) ÷ -2bc
3
Q
cos rule (use when 2 sides and an enclosed angle are given)
A
a² = b² + c² -2bc.cosA
OR b² = a² + c² -2ac.cosB
OR c² = b² + a² -2ab.cosC
4
Q
the area rule
A
half times two sides times the sin of the enclosed angle
area = ½.bc.sinA
OR = ½.ac.sinB
OR = ½.ab.sinC
5
Q
sin rule (use when given 2 sides and an angle)
A
sinA = sinB = sinC
a b c
6
Q
tan identity
A
tanx = sinx
cosx
7
Q
square identity
A
sin²x + cos²x = 1
