Find the sum of 'n' terms in following series
ii) 42+62 +82 + .........
Answers
Answered by
2
Answer:
hey mate!
Step-by-step explanation:
Sn=n/2(2a+(n-1)d);d=20,a=42!
=>n/2(84+(n-1)20)
=>solving this!
=>Sn=62n-20!
ans.!
mark as brainliest!
Answered by
0
given that
a= 42
a2 =62
d=a2 -a
= 62 - 42
= 20
s^n =n/2[2a +(n-1) d]
n/2[2 ×42 + (n-1) × 20]
n/2 [ 84 + 20n-20 ]
n/2 [64 + 20n ]
s ^n = n/2 [64 +20n]
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