Find the sum.
Homework: 9.4 arithmetic series
1 answer:
Answer:
Step-by-step explanation:
a1 = 3(1) - 7 = - 4
a2 = 3(2) - 7 = -1
d = a2 - a1
d = -1 - (-4)
d = -1 + 4
d = 3
a60 = 3(60) - 7
a60 = 180 - 7
a60 = 173
n = 60
Sum = (a1 + a60) * n / 2
Sum = (-4 + 173) * 60/2
Sum = (169)*30
Sum = 5070
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Just to check, we'll use the second summation formula
d = 3
n = 60
a1 = -4
Sum = (2*a1 + (n - 1)*d )*n / 2
Sum = (2*(-4) + (60 -1)*3)* 60/2
Sum = (-8 + 59*3) * 30
Sum = (177 - 8)*30
Sum = 169 * 30
Sum = 5070
Same answer.
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A=24.56
Work circle= 3.14 times 4 Sq/4= 12.56
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B.16.75
OR 12.28+ Sq rt of 20
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Answer:
Imagine that the number that we are looking for is x
We know that:
x/5 - 78 = 9
x/5 = 9 + 78
x/5 = 87
x = 87 . 5 = 435
So the number we need is 435
Answer:
108
Step-by-step explanation:
12/4=3
36 x 3 = 108
Answer:
i think its 24x-12? sorry if it is wrong
