Question

what is the algebraic form of the arithametic sequence of 4,12,20
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Answer 1

Answer:

(a+b)2=2a+(2ab)+ba

Step-by-step explanation:

1. 4,12,20=(ab)=2+(2ab)
2. =(2ab)+bad
3. =2a+(2ab)+ba

Answer 2

Given:-

• First term (a) = 4

To find:-

• Find the sum of n term of an Ap.?

Solutions:-

• Common difference => d =a2 - a1 = 12 - 4 = 8

We have,

The nth terms of an Ap = 8.

=> l = a + (n - 1)d

=> l = 4 + (n - 1)8

=> l = 4 + 8n - 8

=> l = 8n - 4

The sum of n term.

• Sn = n/2 [a + l]

=> Sn = n/2 × [4 + 8n - 4]

=> Sn = n/2 × 8n

=> Sn = n × 4n

=> Sn = 4n²

Hence, the sum of nth term is 4n².

Important formula:-

• A_n = a + (n - 1) d
• S_n = n/2 (a - l)
• S_n = n/2 [2a + (n - 1)] d

More information:-

• a = first terms
• d = common difference
• n = number of terms.
• l = last term
• a_n = nth term