product of real roots of the equation (given below)is: a.always +ve b.always -ve c.does not exist. d.none of these.

Asked by abhilipsa satpathy | 16th Jun, 2013, 03:12: PM

Expert Answer:

Product of roots of a given quadratic equation of the form ax^2 + bx + c = 0 is equal to c/a 
Also, here we are talking of the real roots of the equation only. 
So, D = b^2-4ac > 0 for real roots
D = b^2 - 4*1*9 = b^2 - 36.
Now, b = 1  for x>=0 and b = -1 for x<0. Hence b^2 in both cases would be 1
D = 1-36 = -35
So, the given equation will not have real roots in any case. 
hence, the product of real roots does not exist and hence option c is correct. 

Answered by  | 16th Jun, 2013, 09:09: PM

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