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2019 AMC 12B Question 8

AMC12 · 2019 AMC 12B

Question 8

Let $f(x)=x^2(1-x)^2.$ What is the value of the sum

$$
\begin{gathered} f\!\left(\tfrac{1}{2019}\right)-f\!\left(\tfrac{2}{2019}\right) \\ {}+f\!\left(\tfrac{3}{2019}\right)-f\!\left(\tfrac{4}{2019}\right) \\ {}+\cdots+f\!\left(\tfrac{2017}{2019}\right) \\ {}-f\!\left(\tfrac{2018}{2019}\right)? \end{gathered}
$$
  1. $0$
  2. $\dfrac{1}{2019^4}$
  3. $\dfrac{2018^2}{2019^4}$
  4. $\dfrac{2020^2}{2019^4}$
  5. $1$