If sinA + cosA = , then find the value of tanA+ cotA + 2sinAcosA.
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Correct answer: D
Explanation
The correct answer is option 4 i.e. 3.
sinA + cosA = √3
⇒ (sinA + cosA)2 = (√3)2
⇒ sin2A + 2sinAcosA + cos2A = 3
⇒ 1 + 2sinAcosA = 3 [∵ sin2A + cos2A = 1]
⇒ 2sinAcosA = 2
⇒ sinAcosA = 2/2 = 1
Now, tanA+ cotA + 2sinAcosA
= (sinA/cosA) + (cosA/sinA) + 2
= 1/(sinAcosA) + 2
= 1/1 + 2
= 1 + 2
= 3
Therefore, the value of tanA+ cotA + 2sinAcosA is 3.