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ratelena [41]
3 years ago
5

Which calculation should be used to calculate s9 for the arithmetic sequence an=3n-1

Mathematics
2 answers:
Ganezh [65]3 years ago
7 0

Answer: Choice A

S9 = (9/2)*(2+26)

===============================================

The formula is

Sn = (n/2)*(a1+an)

where

Sn = sum of the first n terms (nth partial sum)

n = number of terms

a1 = first term

an = nth term

In this case,

n = 9

a1 = 2 (plug in n = 1 into the formula an = 3n-1 and simplify)

an = a9 = 26 (plug n = 9 into the formula an = 3n-1 and simplify)

So,

Sn = (n/2)*(a1+an)

S9 = (9/2)*(2+26)

will help us find the sum of the first 9 terms of this arithmetic sequence

mario62 [17]3 years ago
3 0

Answer:

A. S9 = (9/2)*(2+26)


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Answer:

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Step-by-step explanation:

It is a problem about the angular speed of the car's wheel.

You can calculate the angular speed by using the following formula, which relates the tangential speed of the wheels (the same as the speed of the car) with the angular speed:

\omega=\frac{v}{r}    ( 1 )

v: speed of the car = tangential speed of the wheels = 47mph

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next, you replace the values of v and r in the equation (1):

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Then, the car's tires are turning with an angular speed of 3676.44 rad/min

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Step-by-step explanation:

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