Irvin Dukes

2021-12-29

What is the 4th partial sum for the geometric sequence where ${a}_{1}=18\text{}{\textstyle \phantom{\rule{1em}{0ex}}}\text{and}{\textstyle \phantom{\rule{1em}{0ex}}}\text{}r=2$

a)${S}_{4}=-18$

b)${S}_{4}=288$

c)${S}_{4}=152$

d)${S}_{4}=270$

a)

b)

c)

d)

Becky Harrison

Beginner2021-12-30Added 40 answers

Given data is

${a}_{1}=18$

common ratio$\left(r\right)=2$

We have to calculate 4-th partial sum of CnP.

$S={a}_{1}\left(\frac{1-rn}{1-r}\right)$

By putting the values in formulae.

$\Rightarrow S=18\left(\frac{1-{2}^{4}}{1-2}\right)$

$\Rightarrow S=18\left(\frac{1-16}{1-2}\right)$

$\Rightarrow S=18\left(\frac{-15}{-1}\right)$

$\Rightarrow S=18\times 15=270$

So the answer is 270.

common ratio

We have to calculate 4-th partial sum of CnP.

By putting the values in formulae.

So the answer is 270.

deginasiba

Beginner2021-12-31Added 31 answers

We have, sum to n terms of a geometric sequence is given by.

${S}_{n}=\frac{{a}_{1}\{{\left(r\right)}^{n}-1\}}{r-1}\text{}f{\textstyle \phantom{\rule{1em}{0ex}}}\text{or}{\textstyle \phantom{\rule{1em}{0ex}}}\text{}r1$

So, putting given values$n=4$ , we get

${S}_{4}=\frac{18[{\left(2\right)}^{4}-1]}{2-1}=\frac{18(16-1)}{1}=18\times 15=270$

Hence, 4th partial sum$={S}_{4}=270$

Option c is correct

So, putting given values

Hence, 4th partial sum

Option c is correct

user_27qwe

Skilled2022-01-05Added 375 answers

The 4th partial sum of the sequence is the sum of the first 4 terms:

Because the sequence is geometric, any term can be written in terms of the previous one:

a(n) = r a(n - 1) and, more importanly, in terms of the first term a(1), so that

Then the 4th partial sum is

With a(1) = 18 and r = 2 we have

Find the volume V of the described solid S

A cap of a sphere with radius r and height h.

V=??

Whether each of these functions is a bijection from R to R.

a) $f(x)=-3x+4$

b) $f\left(x\right)=-3{x}^{2}+7$

c) $f(x)=\frac{x+1}{x+2}$

?

$d)f\left(x\right)={x}^{5}+1$In how many different orders can five runners finish a race if no ties are allowed???

State which of the following are linear functions?

a.$f(x)=3$

b.$g(x)=5-2x$

c.$h\left(x\right)=\frac{2}{x}+3$

d.$t(x)=5(x-2)$ Three ounces of cinnamon costs $2.40. If there are 16 ounces in 1 pound, how much does cinnamon cost per pound?

A square is also a

A)Rhombus;

B)Parallelogram;

C)Kite;

D)none of theseWhat is the order of the numbers from least to greatest.

$A=1.5\times {10}^{3}$,

$B=1.4\times {10}^{-1}$,

$C=2\times {10}^{3}$,

$D=1.4\times {10}^{-2}$Write the numerical value of $1.75\times {10}^{-3}$

Solve for y. 2y - 3 = 9

A)5;

B)4;

C)6;

D)3How to graph $y=\frac{1}{2}x-1$?

How to graph $y=2x+1$ using a table?

simplify $\sqrt{257}$

How to find the vertex of the parabola by completing the square ${x}^{2}-6x+8=y$?

There are 60 minutes in an hour. How many minutes are there in a day (24 hours)?

Write 18 thousand in scientific notation.