sinθ = 4/5 হলে, ‍tanθ এর মান কোনটি?

প্রশ্ন: sinθ = 4/5 হলে, ‍tanθ এর মান কোনটি?

সমাধান: 
sinθ = 4/5
(sinθ)² = (4/5)²
sin²θ = 16/25
1 - cos²θ =16/25
1 - (16/25) = cos²θ
(25 - 16)/25 = cos²θ
9/25 = cos²θ
(3/5)² = cos²θ
cosθ = 3/5

tanθ = sinθ/cosθ
= (4/5)/(3/5)
= (4/5) × (5/3)
= 4/3