We'll have to differentiate the function for finding the
roots of the expression of the first derivative.
We'll
re-write the function:
f(x) = (x^2 -
2)/(2x-1)
Since the given function is a product, we'll
apply the quotient rule:
f'(x) = [(x^2-2)'*(2x-1)
- (x^2-2)*(2x-1)']/(2x-1)^2
f'(x) = [2x(2x-1) - 2(x^2 -
2)]/(2x-1)^2
We'll remove the
brackets:
f'(x) = (4x^2 - 2x - 2x^2 +
4)/(2x-1)^2
We'll combine like
terms:
f'(x) = (2x^2 - 2x +
4)/(2x-1)^2
Now, we'll put f'(x) =
0.
(2x^2 - 2x + 4)/(2x-1)^2 =
0
Since the denominator is always positive, for any value
of x, only the numerator could be zero.
2x^2 - 2x + 4 =
0
We'll calculate delta:
delta
= b^2 - 4ac
We'll identify
a,b,c:
a = 2 , b = -2 , c =
4
delta = 4 - 32 = -28 <
0
Since delta is negative and a = 2>0, the
expression 2x^2 - 2x + 4 is always positive for any avlue of
a.
So, the first derivative is positive and
it is not cancelling for any value of a.
The equation f'(x) = 0 has no
roots.
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