RD Sharma - Mathematics

Book: RD Sharma - Mathematics

Chapter: 2. Polynomials

Subject: Maths - Class 10th

Q. No. 3 of CCE - Formative Assessment

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3

If one zero of the polynomial f (x) = (k2 + 4) x2 + 13x + 4k is reciprocal of the other, then k =

Given;


f(x) = (k2 + 4) x2 + 13x + 4k,


One zero of the polynomial is reciprocal of the other,


Let a be the one zero,


The other zero will be 1/a


As we know that,


Product of the zeros = c/a = 4k/k2 + 4


4k/k2 + 4 = 1


4k = k2 + 4


k2 + 4 – 4k = 0


(k – 2)2 = 0


k = 2


So the value of k is 2

Chapter Exercises

More Exercise Questions

8

The sum and product of the zeros of a quadratic polynomial are and — 3 respectively. What is the quadratic polynomial?