Sequences and Series

šŸ•’ Previous Year Questions Stats

Total Questions
Easy Questions
Medium Questions
Hard Questions
11
0
7
4

šŸ“š Key Concepts

  • Sequences and their terms
  • Arithmetic Progression (AP)
    • Common difference
    • nth term
    • Sum of n terms
  • Geometric Progression (GP)
    • Common ratio
    • nth term
    • Sum of n terms
  • Arithmetic Mean (AM)
  • Geometric Mean (GM)
  • AM-GM inequality
  • Relationship between AM and GM
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    šŸŽÆ Key Formulas

  • AP:
    • nth term (aā‚™) = a + (n-1)d
    • Sum (Sā‚™) = n/2[2a + (n-1)d] = n/2(a + l)
  • GP:
    • nth term (aā‚™) = ar^(n-1)
    • Sum (Sā‚™) = a(1-r^n)/(1-r) [r ā‰  1]
    • Sum (Sā‚™) = a(r^n-1)/(r-1) [r > 1]
  • AM = (aā‚ + aā‚‚ + ... + aā‚™)/n
  • GM = āæāˆš(aā‚ Ɨ aā‚‚ Ɨ ... Ɨ aā‚™)
  • AM ā‰„ GM for positive real numbers
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    āš ļø Common Mistakes to Avoid

  • Wrong common difference/ratio identification
  • Incorrect application of sum formulas
  • Confusion between AP and GP
  • Wrong application of AM-GM inequality
  • Errors in term calculations
  • Forgetting conditions for sum of GP
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    šŸ“– Knowledge Prerequisites

  • Basic algebra
  • Number system
  • Exponents and powers
  • Basic inequalities
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    šŸ’” Tips for Students

  • Verify sequence type first
  • Check first few terms to confirm pattern
  • Remember AM ā‰„ GM always
  • Use common difference/ratio to identify progression
  • Practice finding missing terms
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    šŸ‘‰ Practice Recommedations

  • Find terms in sequences
  • Calculate sums of series
  • Solve for missing terms
  • Apply AM-GM inequality
  • Work with arithmetic means
  • Practice geometric means
  • Combine AP and GP concepts
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