Plzzz Help!
Geometric series:
Find a formula for Sn for:
√3 + 3 + 3√3 + 9 + ... to n terms.

Question

Plzzz Help!
Geometric series:
Find a formula for Sn for:
√3 + 3 + 3√3 + 9 + ... to n terms.

anonymous · Answer

$$S _{n}=\frac{ a(1-r ^{n}) }{ 1-r }$$

anonymous · Answer

a=is the first term in the sequence
r=common ratio

anonymous · Answer

if your common ratio is greater than 1,
$$S _{n}=\frac{ a(r ^{n}-1) }{ r-1 }$$

anonymous · Answer

$$S_{n}=\frac{ \sqrt{3} (\sqrt{3}^{n}-1)}{ \sqrt{3} -1}$$
How do I simplify this?
The answer is not this.

anonymous · Answer

what is the answer?

anonymous · Answer

you have the nth term as 
$a_n=3^{n/2}$

anonymous · Answer

and are you sure the sum is not to infinity?

anonymous · Answer

the answer is $$S_{n}=\frac{ 3+\sqrt{3} }{ 2 } ((\sqrt{3})^{n} - 1)$$

anonymous · Answer

they rationalized the denominator.

anonymous · Answer

$$\frac{\sqrt{3}}{\sqrt{3}-1}\times{\sqrt{3}+1\over\sqrt{3}+1}=$$
simplify

anonymous · Answer

ok thnx a lot @kausarsalley and @electrokid !