Question

Find cos θ, if tan θ = 2/3. given 3pi/2 < θ < 2pi

Answer 1

Given: 3 cosθ–4 sin θ = 2 cos θ + sin θ

➪ 3 cos θ - 4 sin θ = 2 cosθ+sinθ

➪ 3cos θ - 2 cosbθ = sinθ + 4 sinθ

➪ cos θ = 5 sinθ

★[Dividing both the sides by cos θ]★

• cos θ/cosθ = 5 sinθ /cosΘ

• 1 = 5 tan θ

• [sinθ /cosΘ = tan Θ]

• tan θ =1/5

✯Hence, tan θ=1/5✯