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PtichkaEL [24]
3 years ago
6

What is the rule for the following sequence: 2, 9, 21, 65

Mathematics
1 answer:
Helga [31]3 years ago
5 0

There is no common ratio or common difference. The first three terms increases more slowly than a cubic, but the last three increase more quickly than the cube of n. The pattern is not obvious to me. When the sequence is cast in recursive terms, you get

... a[n] = (48/13)a[n-2] + (59/39)a[n-1] . . . . a[1] = 2, a[2] = 9

The next term using this rule is 174 34/39, not an integer.

The coefficients p and q for a[n-2] and a[n-1] can be found from

2p+9q=21\\9p+21q=65

_____

Any sequence of 4 numbers can be matched by a polynomial of degree 3 or less. Here, a calculator's polynomial regression function tells us the rule could be

... a[n] = 4.5n³ -24.5n² +49n -27

Using this rule, the next two terms are 168 and 357.

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Will give brainliest amswer ❤️
Fiesta28 [93]

Answer:

78.5 square units

Step-by-step explanation:

d = 10 \implies \: r =  \frac{10}{2} = 5 \\ area \: of \: circle \\= \pi {r}^{2}   \\  = 3.14 \times  {5}^{2}  \\  = 3.14 \times 25 \\  = 78.5  \:  {units}^{2} \\

8 0
3 years ago
Read 2 more answers
Carly wants to add texting to her cell phone plan. She has two choices in texting packages. The TURKEY plan charges $.15 per tex
Usimov [2.4K]

Let x be the number of texts (amount of texts) Carly does in a month.

Let y be the "total" amount Carly will have to pay in a month.

Then, as per the TURKEY plan, Carly's monthly total cost will be represented by the equation as shown: y=0.15x+20

As we can clearly see in the above equation even if Carly does not text a single message (when x=0), even then they will have to pay $20 for that month.

For the GOBBLE plan, the equation will be: y=0.2x.

In this plan as there is no fixed charge, Carly wont have to pay anything extra if they dont make a call.


5 0
3 years ago
LMNO is a parallelogram. If NM = x + 15 and OL = 3x + 5, find the value of x
Sidana [21]
<span>LMNO is a parallelogram
so NM = OL
x + 15 = 3x + 5
solve for x
x - 3x = 5 - 15
-2x = -10
   x = 5

Answer
x = 5</span>
5 0
3 years ago
Read 2 more answers
Find a particular solution to the nonhomogeneous differential equation y??+4y?+5y=?10x+e^(?x).
Firdavs [7]

Answer:

A) Particular solution:

2x+\frac{1}{2}e^{-x}-\frac{8}{5}

B) Homogeneous solution:

y_{h}=e^{-2x}(c_{1}cos(x)+c_{2}sin(x))

C) The most general solution is

y=e^{-2x}(c_{1}cos(x)+c_{2}sin(x))+2x+\frac{1}{2}e^{-x}-\frac{8}{5}

Step-by-step explanation:

Given non homogeneous ODE is

y''+4y'+5y=10x+e^{-x}---(1)

To find homogeneous solution:

D^{2}+4D+5=0\\D^{2}+4D+4-4+5=0\\\\(D+2)^{2}=-1\\D+2=\pm iD=-2 \pm i\\y_{h}=e^{-2x}(c_{1}cos(x)+c_{2}sin(x))---(2)

To find particular solution:

y_{p}=Ax+B+Ce^{-x}\\\\y'_{p}=A-Ce^{-x}\\y''_{p}=Ce^{-x}\\

Substituting y_{p},y'_{p},y''_{p} in (1)

y''_{p}+4y'_{p}+5y_{p}=10x+e^{-x}\\Ce^{-x}+4(A-Ce^{-x})+5(Ax+B+Ce^{-x})=10x+e^{-x}\\

Equating the coefficients

5Ax+2Ce^{-x}+4A+5B=10x+e^{-x}\\5A=10\\A=2\\4A+5B=0\\B=-\frac{4A}{5}B=-\frac{8}{5}2C=1\\C=\frac{1}{2}\\So,\\y_{p}=2x+\frac{1}{2}e^{-x}-\frac{8}{5}---(3)\\

The general solution is

y=y_{h}+y_{p}

from (2) ad (3)

y=e^{-2x}(c_{1}cos(x)+c_{2}sin(x))+2x+\frac{1}{2}e^{-x}-\frac{8}{5}

6 0
3 years ago
Angle a​ and​ ​angle b​ ​are complementary angles. The measure of ∠a is 42°.
Citrus2011 [14]
My work to your question
8 0
3 years ago
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