Question

Write the acute angle θ satisfying \[\cos B = \frac{3}{5}\]

Answer 1

We have:  `sqrt3 sinθ = cosθ`

⇒ `sqrt3 sin θ=cos θ` 

⇒` sinθ/cos θ=1/sqrt3` 

⇒ `tan θ= tan 30°` 

⇒`θ=30°` 

Hence the acute angle is 30°`