What are the critical points of (x^2/(x^2-1))(x2x21)?

1 Answer
Mar 28, 2015

I will put f(x) in front of (x^2/(x^2-1))(x2x21)

To find the critical number, you must get the first derivative of
f(x) = (x^2/(x^2-1))(x2x21)

The first derivative is f^'(x) = (-2x)/(x^2-1)^2

Now you must set f^'(x) = 0, and you must also find where the f^'(x) does not exist (dne).

f^'(x) = 0 ------------------------- f^'(x) dne

(-2x)/(x^2-1)^2 = 0 ------------------f^'(x) dne at x = 1 and x = -1

-2x = 0
x = 0 ------------------------------now you must plug them back to the
---------------------------------------- back to the original equation.
---------------------------------------Since x = 1 and x = -1 are undefined, they --------------------------------------------------------are not critical numbers

Since x = 0 is defined in the original equation, it is a critical number.