Let T1 = 1, T2 = 2, T3 = 4, and Tn = Tn-1 + Tn-2 + Tn-3 for n ≥ 4. Class 9

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· Jul 10, 2026 · Reviewed & updated Sep 17, 2026 · 1 min read

Let T1 = 1, T2 = 2, T3 = 4, and Tn = Tn-1 + Tn-2 + Tn-3 for n ≥ 4. Class 9

Question 1.

Let T1 = 1, T2 = 2, T3 = 4, and Tn = Tn-1 + Tn-2 + Tn-3 for n ≥ 4. Class 9

Find T4, T5 T6, T7, and T8.

Solution:

Given,

T1 = 1, T2 = 2, T3 = 4 and

Tn = Tn-1 + Tn-2 + Tn-3 for n ≥ 4

Substituting n = 4, 5, 6, 7, and 8 in the given recursive rule, we get

T4 = T3 + T2 + T1 = 4 + 2 + 1 = 7

T5 = T4 + T3 + T2 = 7 + 4 + 2 = 13

T6 = T5 + T4 + T3 = 13 + 7 + 4 = 24

T7 = T6 + T5 + T4 = 24 +13 + 7 = 44

T8 = T7 + T6 + T5 = 44 + 24 + 13 = 81

∴ Required terms are 7, 13, 24, 44, 81.