Question

Compute each sum below. If applicable, write your answer as a fraction.

Answer 1

Answer:

First equation is -425

Second equation is 11.25

Step-by-step explanation:

First equation we can write as

$\sum_{i=0}^7 5 \times (-2)^i$

computing

When i=0 -> $5 \times (-2)^0 =5$

When i=1 -> $5 \times (-2)^1 = -10$

...

When i=7 -> $5 \times (-2)^7 = --640$

then replacing each term we have

$5 + (-10) + ( 20) + ( -40) + (80) +( -160) + 320 + (-640) = -425$

For the second equation we'll have 9 terms, solving in a similar fashion

When i=1 -> $\frac{1}{4}1=0.25$

When i=2 -> $\frac{1}{4}2=0.50$

When i=3 -> $\frac{1}{4}3=0.75$

...

When i=9 -> $\frac{1}{4}9=2.25$

So we have 0.25 + 0.50 + 0.75 + 1.00 + 1.25 + 1.50+ 1.75 +2.00 +2.25