1.

If sinθ + cosecθ = 2, then find the value of sin2θ + cos4θ - 2cosec2θ.1. -12. 13. -24. 2

Answer» Correct Answer - Option 1 : -1

Given:

sinθ + cosecθ = 2

Formula used:

sin90° = 1

cos90° = 0

cosec90° = 1

sinθ = 1/cosecθ 

Calculation:

sinθ + cosecθ = 2

⇒ sinθ + (1/sinθ) = 2

But the above equation possible when sinθ = 1

⇒ sinθ = sin90° 

After comparing we get θ = 90° 

sin2θ + cos4θ - 2cosec2θ

⇒ sin290° + cos490° - 2cosec290°

⇒ (1)2 + (0)4 - 2 × (1)2

⇒ 1 + 0 - 2

⇒ -1

∴ The value is -1.



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