Write the first four terms of the sequence whose general term is given below.

Question

a_n=(-1)ⁿ⁺¹(n+6)

a₁=

a₂=

a₃=

a₄=

Answer 1

The first term is when n = 1

a₁ = (-1)¹⁺¹(1 + 6)

a₁ = (-1)²(7)

a₁ = (1)(7) = 7

The second term is when n = 2:

a₂ = (-1)²⁺¹(2 + 6)

a₂ = (-1)³(8)

a₂ = (-1)(8) = -8

The third term is when n = 3

a₃ = (-1)³⁺¹(3 + 6)

a₃ = (-1)⁴(9)

a₃ = (1)(9) = 9

The fourth term is when n = 4:

a₄ = (-1)⁴⁺¹(4 + 6)

a₄ = (-1)⁵(10)

a₄ = (-1)(10) = -10