Answer:Answer:
Step-by-step explanation:
Given the sequence -4,-6,-8..., in order to get sigma notation to represent the sum of the first seven terms of the sequence, we need to first calculate the sum of the first seven terms of the sequence as shown;
The sum of an arithmetic series is expressed as ![S_n = \frac{n}{2}[2a+(n-1)d]](https://tex.z-dn.net/?f=S_n%20%3D%20%5Cfrac%7Bn%7D%7B2%7D%5B2a%2B%28n-1%29d%5D)
n is the number of terms
a is the first term of the sequence
d is the common difference
Given parameters
n = 7, a = -4 and d = -6-(-4) = -8-(-6) = -2
Required
Sum of the first seven terms of the sequence
![S_7 = \frac{7}{2}[2(-4)+(7-1)(-2)]\\\\S_7 = \frac{7}{2}[-8+(6)(-2)]\\\\S_7 = \frac{7}{2}[-8-12]\\\\\\S_7 = \frac{7}{2} * -20\\\\S_7 = -70](https://tex.z-dn.net/?f=S_7%20%3D%20%5Cfrac%7B7%7D%7B2%7D%5B2%28-4%29%2B%287-1%29%28-2%29%5D%5C%5C%5C%5CS_7%20%3D%20%20%5Cfrac%7B7%7D%7B2%7D%5B-8%2B%286%29%28-2%29%5D%5C%5C%5C%5CS_7%20%3D%20%20%5Cfrac%7B7%7D%7B2%7D%5B-8-12%5D%5C%5C%5C%5C%5C%5CS_7%20%3D%20%5Cfrac%7B7%7D%7B2%7D%20%2A%20-20%5C%5C%5C%5CS_7%20%3D%20-70)
The sum of the nth term of the sequence will be;
![S_n = \frac{n}{2}[2(-4)+(n-1)(-2)]\\\\S_n = \frac{n}{2}[-8+(-2n+2)]\\\\S_n = \frac{n}{2}[-6-2n]\\\\S_n = \frac{-6n}{2} - \frac{2n^2}{2}\\S_n = -3n-n^2\\\\S_n = -n(3+n)](https://tex.z-dn.net/?f=S_n%20%3D%20%5Cfrac%7Bn%7D%7B2%7D%5B2%28-4%29%2B%28n-1%29%28-2%29%5D%5C%5C%5C%5CS_n%20%3D%20%5Cfrac%7Bn%7D%7B2%7D%5B-8%2B%28-2n%2B2%29%5D%5C%5C%5C%5CS_n%20%3D%20%5Cfrac%7Bn%7D%7B2%7D%5B-6-2n%5D%5C%5C%5C%5CS_n%20%3D%20%20%5Cfrac%7B-6n%7D%7B2%7D%20-%20%20%5Cfrac%7B2n%5E2%7D%7B2%7D%5C%5CS_n%20%3D%20-3n-n%5E2%5C%5C%5C%5CS_n%20%3D%20-n%283%2Bn%29)
The sigma notation will be expressed as . <em>The limit ranges from 1 to 7 since we are to find the sum of the first seven terms of the series.</em>
Answer:
8463/32=264 15/32
Step-by-step explanation:
Let's make every fraction improper first.
7 3/4=31/4
5 2/8=42/8
6 1/2=13/2
Simplify 42/8
42/8=21/4
21/4
31/4
13/2=26/4
21/14*31/4*26/4=(21*31*26)/64=16926/64=8463/32
Step-by-step explanation:
4^m * 4^2 = 12
4^(m + 2) = 4^(log4 12)
m + 2 = log4 (12)
m = log4 (12) - 2.
D=√(x2-x1)² + (y2-y1)²
D=√(-6 3/4-8 1/2)² + (7 1/2-12)²
D=√(-15 1/4)² + (-4 1/2)²
D=√3721/16 + 81/4
D=√4069/16
D=64/4
D=16
Answer:
19.6 cubic centimeters
Step-by-step explanation:
The ratio of two similar 3D figures' volumes is equivalent to the ratio of their corresponding lengths (whether it's width, height, length, radius, etc) cubed.
Here, we know the cones are similar, and we know the smaller radius is 2 and the larger radius is 3. Then the ratio of the volume of the smaller one to the volume of the larger one is 
.
We also know the actual volume of the larger cone is 66. So, if x is the volume of the smaller cone, we have the proportion:
x / 66 = 8 / 27
Cross-multiply:
27x = 66 * 8 = 528
Divide by 27:
x = 528/27 ≈ 19.6
The answer is thus 19.6 cubic centimeters.
<em>~ an aesthetics lover</em>
