Test:41 QNo:6

find the sum of the roots of the eqn. dy/dx=0, where y=(x⁸+7x⁶+5x⁵+
3x⁴+2x²+1)(3x³+x+3)

2 Answers

106

Asish Mahapatra ·2009-11-07 22:05:34

For sum,
we need coeff of highest power of x and next highest power of x i.e. x¹¹ and x¹⁰ in the polynomial

coeff of x¹¹ = 3
coeff of x¹⁰ = 0

So, in the differentiated polynomial, the coeff of x¹⁰ = 33 and coeff of x⁹ = 0

So, sum of roots = 0

a) 1/33
b) 0
c) -1/33
d) 14/11
Your Answer: (b)
Correct Answer: (a)
Score: -1

exactly!!

a) 1/33
b) 0
c) -1/33
d) 14/11

so correct answer must be (b) not (a)

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