Engineering
Mathematics
Special Types of Sequence
Question

The value of Limn→∞∑r=1n6n−1(3n−2)2⋅(3n+1)2  is L, then 9L is equal to

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Solution

L=13Limn→∞ ∑r=1n(3n+1)2−(3n−2)2(3n−2)2 · (3n+1)2=13Limn→∞ ∑r=1n(1(3n−2)2−1(3n+1)2)=13