Question

If cos A = 4/5 , then the value of tan A is

(A) 3/5 (B) ¾ (C) 4/3 (D) 5/3

Answer 1

(B) 3/4

According to the question,

cos A = 4/5 …(1)

We know,

tan A = sinA/cosA

To find the value of sin A,

We have the equation,

sin² θ +cos² θ =1

So, sin θ = √ (1-cos² θ)

Then,

sin A = √ (1-cos² A) …(2)

sin² A = 1-cos² A

sin A = √(1-cos² A)

Substituting equation (1) in (2),

We get,

Sin A = √(1-(4/5)²)

= √(1-(16/25))

= √(9/25)

= ¾

Therefore,