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Chapter 7 of 10
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Some Special Sequences

NIOS · Class 12 · Mathematics

Flashcards for Some Special Sequences — NIOS Class 12 Mathematics. Quick Q&A cards covering key concepts, definitions, and formulas.

45 questions25 flashcards5 concepts

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Illustrates the definition of a sequence as an ordered collection of objects, showing how terms are indexed by natural numbers and providing simple examples.
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25 Flashcards
Card 1Finding Terms from General Formula

Find the first 6 terms of the sequence where T_n = 2n + 1

Answer

Step 1: Substitute n = 1, 2, 3, 4, 5, 6 into T_n = 2n + 1 Step 2: T_1 = 2(1) + 1 = 3 Step 3: T_2 = 2(2) + 1 = 5 Step 4: T_3 = 2(3) + 1 = 7 Step 5: T_4 = 2(4) + 1 = 9 Step 6: T_5 = 2(5) + 1 = 11 Step 7

Card 2Finding Terms from General Formula

Find the first 6 terms of the sequence where a_n = n² - n + 1

Answer

Step 1: Substitute n = 1, 2, 3, 4, 5, 6 into a_n = n² - n + 1 Step 2: a_1 = (1)² - 1 + 1 = 1 - 1 + 1 = 1 Step 3: a_2 = (2)² - 2 + 1 = 4 - 2 + 1 = 3 Step 4: a_3 = (3)² - 3 + 1 = 9 - 3 + 1 = 7 Step 5: a

Card 3Finding nth Term of a Series

Find the nth term of the series: -2 + 4 - 6 + 8 - ...

Answer

Step 1: Observe the pattern - Terms alternate in sign (negative, positive, negative, positive...) - Absolute values: 2, 4, 6, 8, ... (these are 2n) Step 2: Create the nth term formula - For alternati

Card 4Finding nth Term of a Series

Find the nth term of the series: 4 + 16 + 64 + 256 + ...

Answer

Step 1: Rewrite the series to identify the pattern 4 + 16 + 64 + 256 + ... = 4¹ + 4² + 4³ + 4⁴ + ... Step 2: Verify the pattern - 4¹ = 4 - 4² = 16 - 4³ = 64 - 4⁴ = 256 Step 3: General term Each term

Card 5Sum of Powers of Natural Numbers

Formula for sum of first n natural numbers: Σn = ?

Answer

Formula: Σn = n(n + 1)/2 Where: - n = number of natural numbers to sum - The formula gives the sum 1 + 2 + 3 + ... + n Example: Find sum of first 10 natural numbers Step 1: Use Σn = n(n + 1)/2 Step

Card 6Sum of Powers of Natural Numbers

Find the sum of first 15 natural numbers using the formula Σn = n(n + 1)/2

Answer

Step 1: Identify what we need Sum of 1 + 2 + 3 + ... + 15 Step 2: Use the formula Σn = n(n + 1)/2 Step 3: Substitute n = 15 Σ15 = 15(15 + 1)/2 = 15(16)/2 = 240/2 = 120 Step 4: Verify

Card 7Sum of Powers of Natural Numbers

Formula for sum of squares of first n natural numbers: Σn² = ?

Answer

Formula: Σn² = n(n + 1)(2n + 1)/6 Where: - n = number of terms - This gives 1² + 2² + 3² + ... + n² Example: Find 1² + 2² + 3² + 4² + 5² Step 1: Use Σn² = n(n + 1)(2n + 1)/6 Step 2: Substitute n = 5

Card 8Sum of Powers of Natural Numbers

Find 1² + 2² + 3² + 4² + ... + 10² using the formula for sum of squares

Answer

Step 1: Identify what we need Sum of squares from 1 to 10 Step 2: Use the formula Σn² = n(n + 1)(2n + 1)/6 Step 3: Substitute n = 10 Σ10² = 10(10 + 1)(2·10 + 1)/6 = 10(11)(21)/6 = 2310/6

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Frequently Asked Questions

What are the important topics in Some Special Sequences for NIOS Class 12 Mathematics?
Key topics in Some Special Sequences include Overview of Some Special Sequences Chapter, Mind map showing the relationship between sequences and series, including their types and characteristics, Flowchart showing the step-by-step process of finding terms in a sequence using the nth term formula. These are the concepts NIOS Class 12 examiners draw on most — study them first, then practise related questions.
How to score full marks in Some Special Sequences — NIOS Class 12 Mathematics?
Understand the core concepts first, then work through the 45 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.
How many flashcards are available for Some Special Sequences?
There are 25 flashcards for Some Special Sequences covering key definitions, formulas, and concepts. Use them daily for 10–15 minutes for best results.

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