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Dovator [93]
3 years ago
9

Find S15 for the series -1 + -3 + -5 + -7 +...

Mathematics
1 answer:
Ber [7]3 years ago
8 0
Hello :
the sum is  arithmetic secquence of common -diff is :
(-7)-(-5) =(-5)-(-3) = (-3)-(-1) =-2 = d
  the first term is : a1 = -1
<span>the formula of the sum :  S= (n/2)(a1 +an)
n is number of term       an = a1+(n-1)d</span>
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the equation below shows the relationship between the temperature in degrees celsius C in degrees Fahrenheit f f equals 9/5 C +
Rasek [7]
Use the given equation and solve for C.

F = 9C/5 + 32

F - 32 = 9C/5

5(F-32) = 9C

C = 5(F-32)/9
5 0
3 years ago
PLEASE HURRY!!!!
mestny [16]

d !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1!!!!!!!!!!!!!!!!!!!!!!!!!!!

4 0
3 years ago
The third through the fifth terms of a geometric sequence are given by a3 = 18, a4 = 27 , and a5 = 81/2
Kaylis [27]

Let <em>a</em> be the first term in the sequence. If <em>r</em> is the ratio between consecutive terms, then the second term is <em>ar</em>, the third term is <em>ar </em>^2, the fourth is <em>ar</em> ^3, and so on, up to the <em>n</em>-th term <em>ar</em> ^(<em>n</em> - 1).

So the third, fourth, and fifth terms are such that

<em>ar</em> ^2 = 18

<em>ar</em> ^3 = 27

<em>ar</em> ^4 = 81/2

Solve for <em>a</em> and <em>r</em> :

(<em>ar</em> ^3) / (<em>ar</em> ^2) = 27/18   =>   <em>r</em> = 3/2

<em>ar</em> ^2 = <em>a</em> (3/2)^2 = 9/4 <em>a</em> = 18   =>   <em>a</em> = 8

Then the <em>n</em>-th term in the sequence is

<em>ar</em> ^(<em>n</em> - 1) = 9 (3/2)^(<em>n</em> - 1)

You can rewrite this by first rewriting 9 = 3^2, then

9 (3/2)^(<em>n</em> - 1) = 3^2 * 3^(<em>n</em> - 1) / 2^(<em>n</em> - 1) = 3^(<em>n</em> + 1)/2^(<em>n</em> - 1)

6 0
3 years ago
baseball team played 160 regular season games. The ratio of the number of games they won to the number of games they lost what i
Greeley [361]
53 games , hope this helps
3 0
3 years ago
??????????????????????
Olenka [21]
Well we know that A+B+C=180
and we know that A=45 and B=90
so together there 135     
180-135=45 
so C=45
now we also know that a straight line is 180 degrees so 180-45 =135(angle f)
135+15(angle e)=150
180-150=30
so angle d=30
7 0
3 years ago
Read 2 more answers
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