Join WhatsApp Icon JEE WhatsApp Group
Question 78

If $$f(\theta) = \begin{vmatrix} 1 & \cos\theta & 1 \\ -\sin\theta & 1 & -\cos\theta \\ -1 & \sin\theta & 1 \end{vmatrix}$$ and A and B are respectively the maximum and the minimum values of $$f(\theta)$$, then (A, B) is equal to:

$$f(\theta) = \begin{vmatrix} 1 & \cos \theta & 1 \\ -\sin \theta & 1 & -\cos \theta \\ -1 & \sin \theta & 1 \end{vmatrix}$$

$$f(\theta) = 1(1 + \sin\theta\cos\theta) - \cos\theta(-\sin\theta - \cos\theta) + 1(-\sin^2\theta + 1)$$

$$f(\theta) = 1 + \sin\theta\cos\theta + \sin\theta\cos\theta + \cos^2\theta - \sin^2\theta + 1$$

$$f(\theta) = 2 + 2\sin\theta\cos\theta + (\cos^2\theta - \sin^2\theta)$$

$$f(\theta) = 2 + \sin2\theta + \cos2\theta$$

The range of the trigonometric part is $$[-\sqrt{2}, \sqrt{2}]$$

The required pair $$(A, B)$$ is $$(2 + \sqrt{2}, 2 - \sqrt{2})$$

Get AI Help

Video Solution

video

Create a FREE account and get:

  • Free JEE Mains Previous Papers PDF
  • Take JEE Mains paper tests

JEE Quant Questions | JEE Quantitative Ability

JEE DILR Questions | LRDI Questions For JEE

JEE Verbal Ability Questions | VARC Questions For JEE

Free JEE Topicwise Questions

JEE Magnetic Effects of CurrentJEE Kinematics - 2D MotionJEE Vector AlgebraJEE CirclesJEE Three Dimensional GeometryJEE Work, Energy & PowerJEE Heat TransferJEE Chemical KineticsJEE Straight LinesJEE Rotational MotionJEE Basic Principles of Organic ChemistryJEE LimitsJEE d and f-Block ElementsJEE p-Block Elements (Groups 13-18)JEE Magnetism & Magnetic MaterialsJEE Surface TensionJEE Electric Charges & FieldsJEE Atoms & NucleiJEE MatricesJEE Atomic StructureJEE Inverse Trigonometric FunctionsJEE Laws of ThermodynamicsJEE ElectrochemistryJEE Units & MeasurementsJEE DifferentiationJEE Hydrocarbons - AlkynesJEE Alcohols, Phenols & EthersJEE Laws of MotionJEE Differential EquationsJEE Electromagnetic WavesJEE Quadratic EquationsJEE Practical Organic ChemistryJEE BiomoleculesJEE Simple Harmonic MotionJEE Alternating CurrentsJEE Laboratory Experiments - XIJEE Complex NumbersJEE Electronic DevicesJEE Coordination CompoundsJEE DeterminantsJEE Trigonometric FunctionsJEE Kinematics - 1D MotionJEE Definite IntegrationJEE Chemical Bonding & Molecular StructureJEE EquilibriumJEE SolutionsJEE Hydrocarbons - AromaticJEE Binomial TheoremJEE Redox ReactionsJEE Number SystemJEE Nitrogen-Containing CompoundsJEE Conic SectionsJEE GravitationJEE Permutations & CombinationsJEE JEE 2D GeometryJEE Dual Nature of Matter & RadiationJEE Chemical ThermodynamicsJEE Purification & CharacterisationJEE Basic Concepts in ChemistryJEE Sets, Relations & FunctionsJEE Organic Compounds with HalogensJEE Periodic Table & PeriodicityJEE Continuity & DifferentiabilityJEE Current & ResistanceJEE StatisticsJEE Indefinite IntegrationJEE Wave OpticsJEE Aldehydes & KetonesJEE Hydrocarbons - AlkenesJEE Electric Potential & CapacitanceJEE Applications of DerivativesJEE Carboxylic AcidsJEE WavesJEE EMF & Circuit AnalysisJEE Fluid MechanicsJEE Sequences & SeriesJEE ElasticityJEE Hydrocarbons - AlkanesJEE Kinetic Theory of GasesJEE Ray OpticsJEE Electromagnetic InductionJEE Probability
Ask AI