Question

Find the sum: 5-(5/3) (5/9)-(5/27) (5/81)-......

Answer 1

Hello,

If you don't know how to calculate the sum of a geometric progression,

the solution is the file joined.
else
$ratio= \frac{-1}{3} \\ u_{1} =5\\ u_{2} =5* \frac{-1}{3} \\ u_{3} =5* (\frac{-1}{3})^2 \\ u_{4} =5* (\frac{-1}{3})^3 \\ u_{n} =5* (\frac{-1}{3})^{n-1} \\ sum= u_{1} * \dfrac{1}{1-( \frac{-1}{3})} =5*3/4=15/4=3.75$

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