Question

Write the first four terms of the sequence whose nth term is

(a) T_n = 2n − 1

(b) T_n = 5 − 2n

(c) T_n = 3n² + 1

(d) T_n = 3ⁿ⁺¹

Answer 1

(a)

Put n = 1, 2, 3 and 4 successively in T_n to obtain T₁, T₂, T₃ and T₄ respectively.

Thus, the first four terms of the sequence are 1, 3, 5 and 7.

(b)

Put n = 1, 2, 3 and 4 successively in T_n to obtain T₁, T₂, T₃ and T₄ respectively.

Thus, the first four terms of the sequence are 3, 1, 1 and −3.

(c)

Put n = 1, 2, 3 and 4 successively in T_n to obtain T₁, T₂, T₃ and T₄ respectively.

Thus, the first four terms of the sequence are 4, 13, 28 and 49.

(d)

Put n = 1, 2, 3 and 4 successively in T_n to obtain T₁, T₂, T₃ and T₄ respectively.

Thus, the first four terms of the sequence are 1, 3, 9 and 27.