Trig functions and other angle bits

Question 1

Why are small angle approximations called small angle approximations?

Answer 1

Because they only apply to small angles (in radians)

Question 2

What is the equation for arc length?

Answer 2

Length = rθ
(where θ is in radians)

Question 3

What is the equation for area of a sector?

Answer 3

Area = ½r²θ
(where r is in radians)

Question 4

What’s the trig function involving sec & tan?

Answer 4

Sec²θ ≡ 1 + tan²θ

Question 5

What’s the trig function involving cosec & cot?

Answer 5

Cosec²θ ≡ Cot²θ + 1