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  1. If sin θ + cos θ = √2 sin (90° – θ), then the value of cot θ is
    1. – √2 –1
    2. 2 –1
    3. 2 + 1
    4. – √2 + 1
Correct Option: C

sinθ + cosθ = √2 sin (90° – θ)
⇒ sinθ + cosθ = √2 cosθ
⇒ sinθ = √2 cosθ – cosθ
⇒ sinθ = cosθ ( √2 –1)

cos θ
=
1
sin θ2 - 1

⇒ cot θ =
1
2 - 1

⇒ cot θ =
1
×
(√2 + 1)
2 - 1(√2 + 1)

=
2 + 1
= √2 + 1
2 - 1



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