$\bf \sum\limits_{i=a_1}^{a_n}\ a1\cdot (r)^{n-1}\iff S_n=a_1\left( \cfrac{1-r^n}{1-r} \right)\qquad 
\begin{cases}
a_1=\textit{first term}\\
r=\textit{common ratio}\\
n=n^{th}\ term
\end{cases}\\\\
-----------------------------\\\\

\begin{array}{llll}
\sum\limits_{i=1}^{3}\ &4\cdot \left( \frac{1}{2} \right)^{i-1}\\
&\uparrow \quad \uparrow \\
&a_1\quad r
\end{array}\iff S_3=4\left( \cfrac{1-\left( \frac{1}{2} \right)^3}{1-\left( \frac{1}{2} \right)} \right)$

7 0

3 years ago

You need to buy apples that costs $1.40 per pound. the farmer sells her apples in bags, and your bag is 2.5 pounds. How much did

lana [24]

Answer:

$3.50

Step-by-step explanation:

Let's split 2.5 into 2 separate parts, 2 and .5. To find how much 2 pounds of apples cost, we have to multiply $1.40 by 2. 1.40x2= 2.80. Now we have to figure out how much .5 pounds. To do this, we have to divide 1.40 by 2. We get .7. 2.80+ .7= $3.50 [or 3.5]

4 0

3 years ago

Distribute and simplify these radicals.<br> 712 (-1+5)

hjlf

Your answer would be 2848. Always do the equation in the parentheses first, so -1 + 5 is 4. So then you multiply 4 by 712. Hope this helped :)

4 0

3 years ago

Find the sum<br> 10 + 8 + 0.6 + 0.04

Fudgin [204]

10 + 8 + 0.6 + 0.04 = 18.64

7 0

3 years ago

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