NTA Abhyas 2020
- Exam
- NTA Abhyas
- Year
- 2020
- Subject
- Mathematics
- Chapter
- Hyperbola
NTA Abhyas 2020 · Mathematics · Hyperbola
Tangents are drawn from the point (α, β) to the hyperbola 3 x ^ 2 -...
Tangents are drawn from the point to the hyperbola and are inclined at angles to the -axis. If \left(tan \theta\right)\left(tan ϕ\right) = 22{\alpha}^{2} - {\beta}^{2} is
Correct answer
7
Step-by-step solution
Given hyperbola is 3{x}^{2} - 2{y}^{2} = 6 or
Slope form of tangent is or
Tangent from the point \left(\alpha, \beta\right){\left(\beta - m\alpha\right)}^{2} = 2{m}^{2} - 3⇒ {m}^{2}\left({\alpha}^{2} - 2\right) - 2\alpha\betam + {\beta}^{2} + 3 = 0{m}_{1}{m}_{2} = \dfrac{{\beta}^{2} + 3}{{\alpha}^{2} - 2} = 2 = tan \theta tan ϕ∴ {\beta}^{2} + 3 = 2{\alpha}^{2} - 4 ⇒ 7 = 2{\alpha}^{2} - {\beta}^{2}$