If θ lies in the first quadrant and cos θ = 8/17, then find the value of cos(30° + θ) + cos(45° - θ) + cos(120° - θ).

Signs of Trigonometric Functions in Different Quadrants, Cosine of Sum and Difference of Two Angles

Signs of Trigonometric Functions in Different Quadrants, Cosine of Sum and Difference of Two Angles | PadhAiPro