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Let a, b, c be non-zero real numbers suc...

Let `a, b, c` be non-zero real numbers such that ; `int_0^1 (1 + cos^8 x)(ax^2 + bx + c)dx = int_0^2 (1+cos^8 x)(ax^2 + bx +c)dx` then the quadratic equation `ax^2 + bx + c = 0` has -

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The correct Answer is:
B

Consider, `f(x)int_(0)^(1)(1+cos^(8)x)(ax^(2)+bx+c)dx`
Obviously, f(x) is cotinuous and differentiable in the interval [1,2].
Also, `f(1)=f(2)" "["given"]`
`therefore` By Rolle's theorem, there exist atleast one point `k in (1,2),` such that `f'(k)=0.`
Now, `f'(x)=(1+cos^(8)x)(ax^(2)+bx+x)f'(k)=0`
`implies(1+cos^(8)k)(ak^(2)+bk+c)=0`
`impliesak^(2)+bk+c=0," "[as (1+cos^(8)k)ne0]`
`thereforex=k"is root of"ax^(2)+bx+c=0, where kin (1,2)`
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