SSC CGL 2022 PYQ — Question 69

SSC CGL - 12 April 2022 - Shift 1 • Quantitative Aptitude • Q69

If 3sec2 θ + tanθ - 7 =0, 0º < θ < 90º, then what is the value of (2sinθ+3cosθ)(cosecθ+secθ)(2sinθ + 3cosθ)\over (cosec θ + secθ) ?

Show answer & explanation

Correct answer: A

Explanation

The correct answer is option 1 i.e. 5/4.

Given, 3sec2 θ + tanθ - 7 =0

Put θ = 45°

⇒  3sec2 45°+ tan45° - 7 = 3 × 2 + 1 - 7 = 7 - 7 = 0

Thus, θ = 45° satisfies our given equation.

Put θ = 45° in (2sinθ+3cosθ)(cosecθ+secθ)(2sinθ + 3cosθ)\over (cosec θ + secθ)

⇒ (2sinθ+3cosθ)(cosecθ+secθ)(2sinθ + 3cosθ)\over (cosec θ + secθ)  = (2sin45° + 3cos45°)/(cosec45° + sec45°)

⇒ {2 × (1/2)1/2 + 3 × (1/2)1/2}/{(2)1/2 + (2)1/2}

⇒ {5/(2)1/2}/{2 × (2)1/2} = 5/{2 × (2)1/2 × (2)1/2} 

⇒ 5/4