Find the sum of the first 11 terms of the geometric sequence shown below. -3/2, 3, -6, 12...

1 answer:

6 0

$a_1=-\frac{3}{2}$
$a_2=3$

$q=3:(-\frac{3}{2})=3*(-\frac{2}{3})=-2$

$S_{11}=-\frac{3}{2}*\frac{1-(-2)^{11}}{1+2}$
$S_{11}=-\frac{3}{2}*\frac{1-(-2048)}{3}$
$S_{11}=-\frac{3*2049}{2*3}$
$S_{11}=-\frac{2049}{2}$
$S_{11}=-1024\frac{1}{2}=-1024,5$

___________________________
Greetings from Poland :)

You might be interested in

What is the e intermediate step in the form (x+a)^2=b as a result of completing the square for the following equation? x^2+6x+19

igomit [66]

Answers of "a" is -66, 18 pls show how to get to the answer of "a"

8 0

1 year ago

Find the length of dm in the given fig.

lesya692 [45]

Answer:

$DM=12$

Step-by-step explanation:

(Let the point where the altitude from $D$ intersects $AB$ be called as point $E$ .) First, let's find the area of parallelogram $ABCD$ . The area of a parallelogram is simply $b*h=bh$ , where $b$ is the parallelogram's base and $h$ is the parallelogram's height. If we let $AB$ and $DE$ be the base and height respectively, since we are already given their lengths, we know that the area of parallelogram $ABCD$ will be $AB*DE=15*8=120$ .

Now, how does this information matter, you might ask? Well, we can take either $AB$ <em>or </em> $CB$ to be the base and either $DE$ or $DM$ to be the height. In this case, let's take the latter two options, as we are looking to find the length of $DM$ .

Therefore, we know that the area of parallelogram $ABCD$ can also be found by calculating $CB*DM$ . Since we know the values of the area and $CB$ , we can write the following equation to solve for $DM$ :