The sum of the first 20 terms of an arithmetic sequence with the 18th term of 8.1 and a common difference of 0.25 is 124.5
Given,
18th term of an arithmetic sequence = 8.1
Common difference = d = 0.25.
<h3>What is an arithmetic sequence?</h3>
The sequence in which the difference between the consecutive term is constant.
The nth term is denoted by:
a_n = a + ( n - 1 ) d
The sum of an arithmetic sequence:
S_n = n/2 [ 2a + ( n - 1 ) d ]
Find the 18th term of the sequence.
18th term = 8.1
d = 0.25
8.1 = a + ( 18 - 1 ) 0.25
8.1 = a + 17 x 0.25
8.1 = a + 4.25
a = 8.1 - 4.25
a = 3.85
Find the sum of 20 terms.
S_20 = 20 / 2 [ 2 x 3.85 + ( 20 - 1 ) 0.25 ]
= 10 [ 7.7 + 19 x 0.25 ]
= 10 [ 7.7 + 4.75 ]
= 10 x 12.45
= 124.5
Thus the sum of the first 20 terms of an arithmetic sequence with the 18th term of 8.1 and a common difference of 0.25 is 124.5
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Answer:
9.6
2.4.
Step-by-step explanation:
It is easy. If you do with calculator it's easy.
Answer:
5 or 6
Step-by-step explanation:
Solve the "f" function with substitute 4 and solve the "g" function with what we get for the "f" function.
f(4) = 2(8) + 3
f(4) = 16 + 3
f(4) = 19
g(19) = 4(19) - 1
g(19) = 76 - 1
g(19) = 75
Best of Luck!
Answer:
exist in areas like physical science, electronics, business, and social sciences. hope this helps
Step-by-step explanation: