Question

What is the recursive definition for 25,20,15,10?

Answer 1

aₙ = 30 - 5n

Explanation:

25,20,15,10, ...

We see from the given series that it is AP with:

• First term = 25
• Common difference = -5 and it is decreasing series

Then formula is:

• aₙ= a₁ + (n-1)d
• aₙ= 25 + (n-1)(-5)
• aₙ= 25 - 5n + 5
• aₙ = 30 - 5n