Given,3cos2θ + 7sin2θ = 4⇒ 3cos2θ + 3sin2θ + 4sin2θ = 4⇒ 3(cos2θ + sin2θ) + 4sin2θ = 4⇒ 3 + 4sin2θ = 4[as sin2θ + cos2θ = 1]⇒ 4sin2θ = 1⇒ θ = 30°[as ]⇒ cot θ = √3[ as cot 30° = √3]

Q. 11 A3.7( 6 Votes )

If 3 cos^2</s

Class 10th RS Aggarwal - Mathematics 20. Summative Assessment I

Answer :

Given,

3cos²θ + 7sin²θ = 4

⇒ 3cos²θ + 3sin²θ + 4sin²θ = 4

⇒ 3(cos²θ + sin²θ) + 4sin²θ = 4

⇒ 3 + 4sin²θ = 4

[as sin²θ + cos²θ = 1]

⇒ 4sin²θ = 1

⇒ θ = 30°

[as ]

⇒ cot θ = √3

[ as cot 30° = √3]

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If 3 cos2</s

If 3 cos^2</s