JEE Main 2018MathematicsQuadratic EquationMediumMCQ

JEE Main 2018 — Quadratic Equation Question with Solution

JEE Main 2018 (16 Apr Online)

Question

If an angle A of a ΔABC satisfies 5cosA+3=0, then the roots of the quadratic equation 9x2+27x+20=0 are

Choose an option

Show full solutionCorrect option: B
Correct answer
BsecA, tanA

Step-by-step explanation

We have,

5cosA+3=0⇒cosA=-35

Clearly, A∈90°,180°

Now, roots of equation

9x2+27x+20=0 

⇒x=-27±729-72018=-27±318

⇒x=-53, -43

Then, -53=secA and -43=tanA.

Hence, the roots are secA and tanA.

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About this question

This is a previous-year question from JEE Main 2018, covering the Quadratic Equation chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.