Use sigma notation to represent the sum of the first seven terms of the following sequence: 4, 10, 16, … the summation from n eq

uals 1 to 7 of negative 4 plus 6 times n the summation from n equals 1 to 7 of 4 plus 6 times n the summation from n equals 1 to 7 of 2 plus 6 times n the summation from n equals 1 to 7 of negative 2 plus 6 times n

Mathematics

1 answer:

Dominik [7]3 years ago

6 0

$\bf 4~~,~~\stackrel{4+6}{10}~~,~~\stackrel{10+6}{16}~~,~~...~\hspace{10em}\stackrel{\textit{common difference}}{d = 6} \\\\[-0.35em] ~\dotfill\\\\ n^{th}\textit{ term of an arithmetic sequence} \\\\ a_n=a_1+(n-1)d\qquad \begin{cases} a_n=n^{th}\ term\\ n=\textit{term position}\\ a_1=\textit{first term}\\ d=\textit{common difference}\\[-0.5em] \hrulefill\\ a_1=4\\ d = 6 \end{cases} \implies a_n=4+(n-1)6 \\\\\\ a_n=4-6+6n\implies a_n=6n-2~\hfill \displaystyle\boxed{\sum\limits_{n = 1}^{7}~6n-2}$

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Which ratios are equivalent ratios for 10/20

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Ashley uses 1/4 package of raisin for a fruit cake. She then uses 1/9 of the remainder for muffins. What fraction of the package

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One gallon of paint covers 400 square feet of surface area. A typical spherical water tower holds 66,840.28 cubic feet of water.

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Answer: There will enough to paint the outside of a typical spherical water tower.

Step-by-step explanation:

1. Solve for the radius r from the formula for calculate the volume of a sphere. as following:

$V=\frac{4}{3}r^{3}\pi\\\frac{3V}{4\pi}=r^{3}\\r=\sqrt[3]{\frac{3V}{4\pi}}$

2. Substitute values:

$r=\sqrt[3]{\frac{3(66,840.28ft^{3})}{4\pi}}=25.17ft$

3. Substitute the value of the radius into the equation fo calculate the surface area of a sphere, then you obtain that the surface area of a typical spherical water tower is:

$SA=4r^{2}\pi\\SA=4(25.17ft)^{2} \pi\\SA=7,964.95ft^{2}$

3. If a city has 25 gallons of paint available and one gallon of paint covers 400 square feet of surface area, you must multiply 25 by 400 square feet to know if there will be enough to paint the outside of a typical spherical water tower.

$25*400ft^{2}=10,000ft^{2}$