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Find the General Term of a Sequence (Tn) – Practice Questions for CAT/XAT

Sequence-Series
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Find the General Term of a Sequence (Tn) – Practice Questions for CAT/XAT

General Term Finder – CAT/XAT Series Questions

🧠 Find the General Term \(T_n\) – CAT/XAT Series Practice

In these 5 carefully curated sets, you're given the first few terms of a series. Your task is to find the general term and answer other related questions. Click to reveal the solutions below each question set.

🔷 Set 1 (Quadratic)

Given terms: 6, 12, 22, 36, 54, 76,..

  1. Find the general term \(T_n\)
  2. What is the degree of the general term?
  3. What is the degree of the summation formula \(\sum T_n\)?
  4. What is the next term (6th)?
  5. Find the 10th term
Click to see solution and answers

\( T_n = 2n^2 + 4 \)

  • Degree of general term: 2
  • Degree of summation: 3
  • 6th term: \( T_6 = 2(36) + 4 = \boxed{76} \)
  • 10th term: \( T_{10} = 2(100) + 4 = \boxed{204} \)

🔷 Set 2 (Quadratic)

Given terms: 7, 14, 25, 40, 59, 82,..

  1. Find the general term \(T_n\)
  2. What is the degree of the general term?
  3. What is the degree of the summation formula \(\sum T_n\)?
  4. What is the next term (6th)?
  5. Find the 10th term
Click to see solution and answers

\( T_n = 2n^2 + n + 4 \)

  • Degree of general term: 2
  • Degree of summation: 3
  • 6th term: \( T_6 = 2(36) + 6 + 4 = \boxed{76} \)
  • 10th term: \( T_{10} = 2(100) + 10 + 4 = \boxed{214} \)

🔶 Set 3 (Cubic)

Given terms: 4, 14, 38, 82, 152, 254,..

  1. Find the general term \(T_n\)
  2. What is the degree of the general term?
  3. What is the degree of the summation formula \(\sum T_n\)?
  4. What is the next term (6th)?
  5. Find the 10th term
Click to see solution and answers

\( T_n = n^3 + n^2 + 2 \)

  • Degree of general term: 3
  • Degree of summation: 4
  • 6th term: \( T_6 = 216 + 36 + 2 = \boxed{254} \)
  • 10th term: \( T_{10} = 1000 + 100 + 2 = \boxed{1102} \)

🔶 Set 4 (Cubic)

Given terms: 1, 6, 29, 82, 177, 326,..

  1. Find the general term \(T_n\)
  2. What is the degree of the general term?
  3. What is the degree of the summation formula \(\sum T_n\)?
  4. What is the next term (6th)?
  5. Find the 10th term
Click to see solution and answers

\( T_n = 2n^3 - 3n^2 + 2 \)

  • Degree of general term: 3
  • Degree of summation: 4
  • 6th term: \( T_6 = 432 - 108 + 2 = \boxed{326} \)
  • 10th term: \( T_{10} = 2000 - 300 + 2 = \boxed{1702} \)

🔺 Set 5 (Quartic)

Given terms: 2, 17, 82, 257, 626, 1297,..

  1. Find the general term \(T_n\)
  2. What is the degree of the general term?
  3. What is the degree of the summation formula \(\sum T_n\)?
  4. Find the next term (6th term)
  5. Find the 10th term
  6. Briefly explain how the degree was identified
  7. Comment on the nature of growth of the sequence (Linear / Polynomial / Exponential)
Click to see solution and answers

\( T_n = n^4 + 1 \)

  • Degree of general term: 4
  • Degree of summation: 5
  • 6th term: \( T_6 = 1296 + 1 = \boxed{1297} \)
  • 10th term: \( T_{10} = 10000 + 1 = \boxed{10001} \)
  • Explanation: Repeated difference method shows 4th difference as constant ⇒ degree = 4
  • Growth Type: Polynomial (quartic) – grows rapidly but slower than exponential