Answer:
Step-by-step explanation:
15) 1
16) 4
17) 21.95
You can try to show this by induction:
• According to the given closed form, we have
, which agrees with the initial value <em>S</em>₁ = 1.
• Assume the closed form is correct for all <em>n</em> up to <em>n</em> = <em>k</em>. In particular, we assume

and

We want to then use this assumption to show the closed form is correct for <em>n</em> = <em>k</em> + 1, or

From the given recurrence, we know

so that






which is what we needed. QED
Answer:
A) [First try is correct for all U1 to U4]
Step-by-step explanation:
1. Trying each option
(let x = 1,2,3,4) since it goes from U1 to U4 (Geometric sequence)
A.) 10(-4/5)^x
10(-4/5)^1 = -8
10(-4/5)^2 = 6.4
10(-4/5)^3 = -5.12
10(-4/5)^4 = 4.096