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Stolb23 [73]
3 years ago
10

The first term in a geometric series is 64 and the common ratio is 0.75. Find the sum of the first 4 terms in the series.

Mathematics
1 answer:
maks197457 [2]3 years ago
4 0

Answer:

195.25

Step-by-step explanation:

Consider geometric series  S(n) where initial term is a

So S(n)=a+ar^1+...ar^n

Factor out a

S(n)=a(1+r+r^2...+r^n)

Multiply by r

S(n)r=a(r+r^2+r^3...+r^n+r^n+1)

Subtract S(n) from S(n)r

Note that only 1 and rn^1 remain.

S(n)r-S(n)=a(r^n+1  -1)

Factor out S(n)

S(n)(r-1)=a(r^n+1  -1)

The formula now shows S(n)=a(r^n+1  -1)/(r-1)

Now use the formula for the problem

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Please please please NO LINKS Find the value of x and NL ! This is really important no links please
poizon [28]

Answer:

x=27 and NL = 40

Step-by-step explanation:

by properties of secants starting from common point-

LK x LJ = LM x LN

10 * (10+42) = 13 * (13+X)

X = 27

6 0
3 years ago
13. Find the surface area of each figure to the nearest tenth. Show your work.
stiv31 [10]
A. The figure is a triangular pyramid. You can findits surface area by adding up the area of the three faces of the triangle and the area of the base. A derived formula also is used where the SA is equal to 12 times the perimeter of base times the slant height, added to that is the area of the base. The area of the square base is s^2. Its perimeter is 4s.

SA of Pyramid = 12*P*l + s^2
SA of Pyramid = 12*4s*l + 16^2
SA of Pyramid = 12*4(16)*(17) + (16)^2
SA of Pyramid = 11,008 square inches

b.) The formula for the SA of a cone is: 

SA of cone = πr[r+√(h^2+r^2)]
SA of cone = π(3)[(3+√(8^2+3^2)]
SA of cone = 108.8 square inches
7 0
3 years ago
Read 2 more answers
A number is chosen at random from 1 to 10. Find the probability of not selecting
PilotLPTM [1.2K]

Answer:

0.3

Step-by-step explanation:

Number of ways of selecting  r elements from a set of n different elements is given by

C(n,r)=(n r)=n!/(r!(n−r)!)

No of ways of selecting one number out of ten numbers from one to 10 is 10

It can also be calculated using  

C(n,r)=(n r)=n!/(r!(n−r)!)

where n = 10 and r = 1

C(10,1)=(10 1)=10!(1!(10−1)!) = 10*9!/ 1!*9! = 10

multiples of 2 in range 1 to 10 are 2, 4, 6, 8 , 10

multiples of 3 in range 1 to 10 are 3, 6, 9

Therefore number which are multiple of 2 and 3 are

2, 3,4,6,8,9,10   ( 7 numbers)

therefore no of ways of selecting multiple of 2 and 3 is 7 ways

number which are not multiple of 2 and 3 in range 1 to 10

1,5,7  (3 numbers)

no of ways of not selecting multiple of 2 and 3 is 3 ways

It can also be calculated using  

C(3,1)=(3 1)=3!/(1!(3−1)!)

where n = 3 and r = 1

C(3,1)=(3 1)=3!/(1!(3−1)!) =  3!/(1!(2)!)= 3*2!/ 1!*2! = 2

Therefore no of ways of not selecting multiple of 2 and 3 is 3 ways

probability of  not selecting  a multiple of 2 or a multiple of 3 =  no of ways of not selecting multiple of 2 and 3 /No of ways of selecting one number out of one to 10  = 3/10 = 0.3

4 0
3 years ago
An item is regularly priced at $75. It is now priced at a discount of 35% off the regular price. Find the price now.
Reptile [31]

Answer:

48.75

Step-by-step explanation:

5 0
3 years ago
people with severe hearing loss given a sentence and word recognition test six months after they got implants in their ears the
kirza4 [7]
That would be .82 as 82% is 82/100 so that makes the answer .82
8 0
3 years ago
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