AP Calculus AB Exam Question:
Let f(x) = (x^2 + 3x - 2) / (x - 1). Using the quotient rule, find the derivative of f(x).
Answer:
To find the derivative of f(x), we will use the quotient rule, which states that for any two functions u(x) and v(x), the derivative of their quotient u(x) / v(x) is given by:
(u'(x) * v(x) - v'(x) * u(x)) / (v(x))^2
Let's apply this rule to our given function:
Given: f(x) = (x^2 + 3x - 2) / (x - 1)
Let u(x) = x^2 + 3x - 2, v(x) = x - 1.
We first need to find u'(x) and v'(x).
Differentiating u(x), we get: u'(x) = 2x + 3
Differentiating v(x), we get: v'(x) = 1
Now, using the quotient rule, the derivative of f(x) is given by:
f'(x) = (u'(x) * v(x) - v'(x) * u(x)) / (v(x))^2
= [(2x + 3) * (x - 1) - 1 * (x^2 + 3x - 2)] / (x - 1)^2
= [2x^2 + 3x - 2x - 3 - x^2 - 3x + 2] / (x - 1)^2
= (x^2 - x - 1) / (x - 1)^2
Thus, the derivative of f(x) is f'(x) = (x^2 - x - 1) / (x - 1)^2.
Note: It is always a good practice to simplify the final expression if possible.