http://www-users.math.umd.edu/~wojte...d_3_sample.pdf
It's #2.
Note: This is only a sample exam.
http://www-users.math.umd.edu/~wojte...d_3_sample.pdf
It's #2.
Note: This is only a sample exam.
We have:
$\displaystyle \displaystyle\sum_{k=1}^{\infty}\dfrac{(-1)^k4^{k-1}}{3^{2k}}}=\dfrac{1}{4}\displaystyle\sum_{k=1}^{ \infty}\left(\frac{-4}{9}\right)^k=\ldots$
Now, use a well known theorem about geometric series.
Regards.
Fernando Revilla
Neither do I.
Regards.
Fernando Revilla