SSC CGL 2023 PYQ — Question 57

SSC CGL - 18 July 2023 - Shift 4 • Quantitative Aptitude • Q57

Find the value of the given expression.

43\frac{4}{3}  tan2 45° + 3 cos2 30° - 2 sec2 30° - 34\frac{3}{4}  cot2 60°

Show answer & explanation

Correct answer: A

Explanation

The correct answer is Option 1 i.e. 23\frac{2}{ 3}.

43\frac{4}{3}  tan2 45° + 3 cos2 30° - 2 sec2 30° - 34\frac{3}{4}  cot2 60°

On putting the values of trigonometric ratios

⇒ tan 45° = 1

⇒ cos 30° = √3/2

⇒ cot 60° = 1/√3

Now,

⇒ 43×(1)2+3×(32)2−2×(23)2−34×(13)2\frac{4}{3} \times (1)^2 + 3\times({\sqrt3\over2})^2 - 2\times ({2\over\sqrt3})^2 - {3\over4} \times ({1\over\sqrt3})^2

⇒ 43+3×(34)−2×(43)−34×(13)\frac{4}{3} + 3\times({3\over4}) - 2\times ({4\over3}) - {3\over4} \times ({1\over3})

⇒ 43+(94)−(83)−14​​\frac{4}{3} + ({9\over4}) - ({8\over3}) - {1\over4}​​

⇒ 1612+(2712)−(3212)−312\frac{16}{12} + ({27\over12}) - ({32\over12}) - {3\over12} = 8128\over12 = 23\frac{2}{ 3}