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olga2289 [7]
3 years ago
13

Find the sum of the first 20 terms of an arithmetic series if the first term is 10 and the twentieth term is 38.

Mathematics
1 answer:
elena-14-01-66 [18.8K]3 years ago
6 0

Answer:480

Step-by-step explanation:

To find the sum of the first n terms of an arithmetic series use the formula, n terms of an arithmetic sequence use the formula,

Sn=n(a1 + an)2

n=20

a1= 10

a20=38

20(10+38)/2

20(48)/2

960/2

480

So the ans is 480

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If f(x)=x^3-x+2, then (f^-1)'(2)
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