f(x) = 3 k x^2 - 18 x + 9 > 0for wat values of x, the given function is increasing ??how to find ??plz explain in detail.....

Dear Mohit,

for increasing func.    dy/dx > 0

6kx - 18 > 0

x > 3/k

For a func to be always positive a > 0 and D < 0   ( for quadratic func. )

so,  3k > 0 and 324 - 4*3k*9 < 0

k > 3

So,  x > 3/k  (where k > 3 ) for the given func. to be always increasing.

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