SSC CGL 2023 PYQ — Question 64

SSC CGL - 18 July 2023 - Shift 3 • Quantitative Aptitude • Q64

Which of the following is a FALSE statement?

Show answer & explanation

Correct answer: A

Explanation

The correct answer is Option 1 i.e. tan2 A = 1 - sec2 A.

Option 1: tan2A = 1 - sec2A

Solving R.H.S

⇒ 1 - sec2A

⇒ 1 - 1/cos2A

⇒ (cos2A - 1)/cos2A

⇒ -sin2A/cos2A = -tan2A

Option 2: sinA = tanA × cosA

Solving R.H.S

⇒ tanA × cosA = sinA/cosA × cosA = sinA

Option 3: cosec2A - 1 = cot2A

Solving L.H.S

⇒ cosec2A - 1 = 1/sin2A - 1

⇒ (1 - sin2A)/sin2A

⇒ cos2A/sin2A = tan2A

Option 4: cosA × secA = 1

⇒ Solving L.H.S

⇒ cosA × secA = 1/secA × secA = 1

Thus, only Option 1 is incorrect