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2 years ago

HELPpPpppppppppppppppppppppppppp and explain

Mathematics

1 answer:

Bess [88]2 years ago

8 0

Answer:

378

Step-by-step explanation:

12 x 18=216

9 x 9= 81

81 x 2= 162

162 + 216 = 378

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Identify whether the series sigma notation infinity i=1 15(4)^i-1 is a convergent or divergent geometric series and find the sum

const2013 [10]

Answer: The correct option is

(d) This is a divergent geometric series. The sum cannot be found.

Step-by-step explanation: The given infinite geometric series is

$S=\sum_{i=1}^{\infty}15(4)^{i-1}.$

We are to identify whether the given geometric series is convergent or divergent. If convergent, we are to find the sum of the series.

We have the D' Alembert's ratio test, states as follows:

Let, $\sum_{i=1}^{\infty}a_i$ is an infinite series, with complex coefficients $a_i$ and we consider the following limit:

$L=\lim_{i\rightarrow \infty}\dfrac{a_{i+1}}{a_i}.$

Then, the series will be convergent if L < 1 and divergent if L > 1.

For the given series, we have

$a_i=15(4)^{i-1},\\\\a_{i+1}=15(4)^i.$

So, the limit is given by

$L\\\\\\=\lim_{i\rightarrow \infty}\dfrac{a_{i+1}}{a_i}\\\\\\=\lim_{i\rightarrow \infty}\dfrac{15(4)^i}{15(4)^{i-1}}\\\\\\=\lim_{i\rightarrow \infty}\dfrac{15(4)^i}{15(4)^{i}4^{-1}}\\\\\\=\dfrac{1}{4^{-1}}\\\\=4>1.$

Therefore, L >1, and so the given series is divergent and hence we cannot find the sum.

Thuds, (d) is the correct option.

7 0

3 years ago

Read 2 more answers

Find the surface area.

denpristay [2]

Step-by-step explanation:

a rectangular prism (like this brick) has the same basic structure as a cube (like a die) : it has 6 sides.

while a die has 6 equal sides, a rectangular prism has 3 pairs of equal sides :

top and bottom

left and right

front and back

all we have to do is calculate the areas of the 6 rectangles and add them up. that's it.

your remember, the area of a rectangle is

length × width

in our case we have

top and bottom : 2.5×11.5 × 2 = 28.75×2 = 57.5 in²

left and right : 2.5×5 × 2 = 12.5×2 = 25 in²

front and back : 11.5×5 × 2 = 57.5×2 = 115 in²

so, the total surface area of the whole block is

57.5 + 25 + 115 = 197.5 in²

5 0

2 years ago

This is a pre calculus question that I need help with, serious answer PLEASE and thank you! Will give brainliest.

IRISSAK [1]

The wording of this question is a bit confusing... You can't write a sequence in sigma notation, but rather a series or sum. I think the question is asking you to write the sum of the sequence,

$\dfrac12,\dfrac14,\dfrac18,\ldots,\dfrac1{64}$

which would be

$\dfrac12+\dfrac14+\dfrac18+\cdots+\dfrac1{64}$

in sigma notation.

To do this, notice that the denominator in each term is a power of 2, starting with $2^1=2$ and ending with $2^6=64$ . So in sigma notation, this series is