Question

tell the whole method
Q12​

Answer 1

Answer:

which class are you studying

Answer 2

Answer:

θ = 45° and 2tan²θ + sin²θ - 1 = 3/2

Step-by-step explanation:

We have,

sinθ = cosθ

⇒ sin² = cos²θ                                          ...(squaring both sides)

⇒ 1 - cos²θ = cos²θ

⇒ 2 cos²θ = 1

⇒ cos²θ = 1/2

⇒ cosθ = 1/√2

⇒ cosθ = cos45°

⇒ θ = 45°                                                  ...(dividing cos on both sides)

Now,

2tan²θ + sin²θ - 1

= 2tan²45° - (1 - sin²θ)

= 2 × 1² - cos²45°

= 2 - (1/√2)²

= 2 - 1/2

= 3/2

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