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  1. If x cos θ – y sin θ = √x² + y²
    cos²θ
    +
    sin²θ
    =
    1
    , then the correct relation is
    x² + y²
    1. -
      = 1
    2. +
      = 1
    3. +
      = 1
    4. -
      = 1
Correct Option: B

According to question,
x cosθ – y sinθ = √x² + y²...(i)

cos²θ
+
sin²θ
=
1
...(ii)
x² + y²


sinθ =
- y
x² + y²

cosθ =
x
x² + y²

From equation (i)
x
cosθ -
y
sinθ = 1
x² + y²x² + y²

cos²θ
+
sin²θ
=
1
x² + y²

+
=
1
(x² + y²)a²(x² + y²)b²x² + y²

+
= 1



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