20 a sequence {an} is defined recursively, with a1 = -1, and, for n > 1, an = an-1 + (-1)n. find the first five terms of the sequence. a) -1, 0, 1, 2, 3 b) -1, -2, -3, -4, -5 c) -1, 0, -1, 0, -1 d) -1, 1, -1, 1, -1

Let's find a₂

From the recursion definition, we know that a₂ = a₁ + (-1)² = a₁ + 1 = 0

Now we know the value of a₂. Now do the same for a₃.

a₃ = a₂ + (-1)³ = a₂ - 1 = -1

So the first three term is -1, 0, -1 and C is only option that matches.

Final C

1. 0.3 •4 is the same as 4 groups of 0.32. 7•0.8 is the same as 7 groups of 0.83. it increases by 0.5 every time, so 0.5x4 it increases by 0.9 every time, so 0.9x5. 0.9•12=10.86. 0.47•5=2.35i can finish the next ones in a separate post