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If tan α + cot α = 2, then tan20α + cot20α = ______.

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Question

If tan α + cot α = 2, then tan20α + cot20α = ______.

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MCQ
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Solution

If tan α + cot α = 2, then tan20α + cot20α = 2.

Explanation:

Given: tan α + cot α = 2

To find: tan20 α + cot20 α

Step 1: Use the identity

Let: x = tan α,then cot α = `1/x`

So, the equation becomes: `x + 1/x = 2`

Multiply both sides by x: 

x2 + 1 = 2x ⇒ x2 − 2x + 1 = 0 ⇒ (x − 1)2 = 0 ⇒ x = 1

So: tan α = 1 ⇒ cot α = 1

Step 2: Substitute into the target expression

tan20 α + cot20 α = 120 + 120 = 1 + 1 = 2

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