Tuesday, July 7, 2015

How to find derivative of f(x)=(2x^2+1)/(2x^2-1)

We notice that we'll have to find the derivative of a
fraction, so, we'll have to use the quotient rule.


(u/v)' =
(u'*v - u*v')/v^2


We'll put u = 2x^2 + 1 => u' =
4x


We'll put v = 2x^2 - 1 => v' =
4x


We'll substitute u,v,u',v' in the formula
above:


f'(x) = [4x*(2x^2 - 1) - (2x^2 + 1)*4x]/(2x^2 -
1)^2


We'll factorize by
4x:


f'(x) = 4x(2x^2 - 1 - 2x^2 - 1)/(2x^2 -
1)^2


We'll combine and eliminate like terms inside
brackets:


f'(x) = 4x *(-2)/(2x^2 -
1)^2


f'(x) = -8x/(2x^2 -
1)^2

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