ExamBro
ExamBro
JEE Mains · Maths · STD 11 - Trigonometrical equations

माना \(S=\left\{\theta \in(0,2 \pi): 7 \cos ^2 \theta-3 \sin ^2 \theta-2\right.\) \(\left.\cos ^2 2 \theta=2\right\}\) है। तब सभी समीकरणों \(x ^2-2\left(\tan ^2 \theta+\cot ^2 \theta\right) x +6 \sin ^2 \theta=0, \theta \in S\) के मूलों का योग है \(..............\)

  1. A \(15\)
  2. B \(14\)
  3. C \(13\)
  4. D \(16\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(16\)

Step-by-step Solution

Detailed explanation

\(7 \cos ^{2} \theta-3 \sin ^{2} \theta-2 \cos ^{2} 2 \theta=2\) \(4 \cos ^{2} \theta+3 \cos 2 \theta-2 \cos ^{2} 2 \theta=2\) \(2(1+\cos 2 \theta)+3 \cos 2 \theta-2 \cos ^{2} 2 \theta=2\) \(2 \cos ^{2} 2 \theta-5 \cos 2 \theta=0\) \(\cos 2 \theta(2 \cos 2 \theta-5)=0\)…
Same subject
Explore more questions on app
From JEE Mains
Explore more questions on app