The sum is equal to...

(b) : We have enumerate (ii) from (i), we get\\...

The sum 1 + 2 \cdot 3 + 3 \cdot 3^{2} + \cdot 10 \cdot 3^{9} is equal to: Sequence & Series (Mathematics)

The sum\n

1 + 2 \cdot 3 + 3 \cdot 3^{2} + \ldots\ldots \cdot 10 \cdot 3^{9}

\n is equal to

\frac{2 \cdot 3^{12} + 10}{4}

\frac{19 \cdot 3^{10} + 1}{4}

5 \cdot 3^{10} - 2

\frac{9 \cdot 3^{10} + 1}{2}