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Ex 8.1, 6
Last updated at June 9, 2026 by Teachoo
Class 9
Chapter 8 - Predicting What Comes Next: Exploring Sequences & Progress
- Definition
- Explicit Rule for a Sequence
- Recursive Rule for a Sequence
- Virahānka–Fibonacci sequence
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Exercise Set 8.1
- Arithmetic Progressions
- Visualising an AP
- Sum of the First n Natural Numbers
- Exercise Set 8.2
- Geometric Progressions
- Fractals as a GP Sequence
- Visualising a GP
- Exercise Set 8.3
- End-of-Chapter Exercises
Transcript
Ex 8.1, 6 Let T_1=1,〖" " T〗_2=2,〖" " T〗_3=4, and T_n=T_(n−1)+T_(n−2)+T_(n−3) for 𝑛≥4. Find T_4,〖" " T〗_5,〖" " T〗_6,〖" " T〗_7, and T_8. Given T_1=1 T_2=2 T_3=4 Using formula 𝑻_𝒏=𝑻_(𝐧−𝟏)+𝑻_(𝐧−𝟐)+𝑻_(𝐧−𝟑) For n ≥ 4 Now, 𝑻_𝟒=𝑇_(4−1)+𝑇_(4−2)+𝑇_(4−3) =𝑻_𝟑+𝑻_𝟐+𝑻_𝟏 =4+2+1 =𝟕 𝑻_𝟓=𝑻_𝟒+𝑻_𝟑+𝑻_𝟐 =7+4+2 =𝟏𝟑 𝑻_𝟔=𝑻_𝟓+𝑻_𝟒+𝑻_𝟑 =13+7+4 =𝟐𝟒 𝑻_𝟕=𝑻_𝟔+𝑻_𝟓+𝑻_𝟒 =24+13+7 =𝟒𝟒 𝑻_𝟖=𝑻_𝟕+𝑻_𝟔+𝑻_𝟓 =44+24+13 =𝟖𝟏
