- √41/2
- 3/2
- √31/3
- √7/9
- 2/3

Option 1 : √41/2

**Given**

tan A = 4/5

**Formula used**

sec^{2 }A = √1 + tan^{2 }A

**Calculation**

tan A = 4/5

sec A = √1 + tan^{2 }A

sec A = √1 + (16/25)

sec A = √(25 + 16)/25

sec A = √41/5

Cot A = 5/4

⇒ 2 × (5/4) × (√41/5)

⇒ √41/2

**∴ 2 cot A × sec A is √41/2**

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