Question

Which of the following is not correct?

Options

• sinθ = `-1/5`

• cosθ = 1

• secθ = `1/2`

• tanθ = 20

Answer 1

`bbunderline(secθ = 1/2)`

Explanation:

We know that,

a) sinθ = `-1/5` is correct since sinθ ∈ [-1, 1]

b) cosθ = 1 is correct since cosθ ∈ [-1, 1]

c) secθ = `1/2`

⇒ `(1/cos θ) = 1/2`

⇒ cosθ = 2 is incorrect since cosθ ∈ [-1, 1]

d) tanθ = 20 is correct since tanθ ∈ R.