Need help on these asap please

Pleas help, I’ll mark as brainliest.

STatiana [176]

Answer:

Step-by-step explanation:

f(4) = -1

g(4) = -2

(f + g)(4) = f(4) + g(4) = -3

Hope that helps!

3 0

2 years ago

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What is the area of this figure?

Luden [163]

Answer:

The area of this figure is 24mm.

Step-by-step explanation:

4mm*3mm=12mm

1mm*6mm=6mm

3mm*4mm=12mm/2mm=6mm

6mm+6mm+12mm=24mm

3 0

2 years ago

Solve for y where y(2)=2 and y'(2)=0 by representing y as a power series centered at x=a

Crank

I'll assume the ODE is actually

$y''+(x-2)y'+y=0$

Look for a series solution centered at $x=2$ , with

$y=\displaystyle\sum_{n\ge0}c_n(x-2)^n$

$\implies y'=\displaystyle\sum_{n\ge0}(n+1)c_{n+1}(x-2)^n$

$\implies y''=\displaystyle\sum_{n\ge0}(n+2)(n+1)c_{n+2}(x-2)^n$

with $c_0=y(2)=2$ and $c_1=y'(2)=0$ .

Substituting the series into the ODE gives

$\displaystyle\sum_{n\ge0}(n+2)(n+1)c_{n+2}(x-2)^n+\sum_{n\ge0}(n+1)c_{n+1}(x-2)^{n+1}+\sum_{n\ge0}c_n(x-2)^n=0$

$\displaystyle\sum_{n\ge0}(n+2)(n+1)c_{n+2}(x-2)^n+\sum_{n\ge1}nc_n(x-2)^n+\sum_{n\ge0}c_n(x-2)^n=0$

$\displaystyle2c_2+c_0+\sum_{n\ge1}(n+2)(n+1)c_{n+2}(x-2)^n+\sum_{n\ge1}nc_n(x-2)^n+\sum_{n\ge1}c_n(x-2)^n=0$

$\displaystyle2c_2+c_0+\sum_{n\ge1}\bigg((n+2)(n+1)c_{n+2}+(n+1)c_n\bigg)(x-2)^n=0$

$\implies\begin{cases}c_0=2\\c_1=0\\(n+2)c_{n+2}+c_n=0&\text{for }n>0\end{cases}$

If $n=2k$ for integers $k\ge0$ , then

$k=0\implies n=0\implies c_0=c_0$

$k=1\implies n=2\implies c_2=-\dfrac{c_0}2=(-1)^1\dfrac{c_0}{2^1(1)}$

$k=2\implies n=4\implies c_4=-\dfrac{c_2}4=(-1)^2\dfrac{c_0}{2^2(2\cdot1)}$

$k=3\implies n=6\implies c_6=-\dfrac{c_4}6=(-1)^3\dfrac{c_0}{2^3(3\cdot2\cdot1)}$

and so on, with

$c_{2k}=(-1)^k\dfrac{c_0}{2^kk!}$

If $n=2k+1$ , we have $c_{2k+1}=0$ for all $k\ge0$ because $c_1=0$ causes every odd-indexed coefficient to vanish.

So we have

$y(x)=\displaystyle\sum_{k\ge0}c_{2k}(x-2)^{2k}=\sum_{k\ge0}(-1)^k\frac{(x-2)^{2k}}{2^{k-1}k!}$

Recall that

$e^x=\displaystyle\sum_{n\ge0}\frac{x^k}{k!}$

The solution we found can then be written as

$y(x)=\displaystyle2\sum_{k\ge0}\frac1{k!}\left(-\frac{(x-2)^2}2\right)^k$

$\implies\boxed{y(x)=2e^{-(x-2)^2/2}}$

6 0

3 years ago

Sally has 39 flowers and Carly has 34 x more than sally how much does sally have

vova2212 [387]

Answer: 1,326

Step-by-step explanation: Multiply 34 times 39

3 0

2 years ago

Cluster sampling and stratified sampling both involve selecting subjects in subgroups of the population. what is the difference

Crank

Cluster sampling and stratified sampling both involve selecting subjects in subgroups of the population. what is the difference between those two types of sampling?

Answer: Cluster sampling and stratified sampling both involve selecting subjects in subgroups of the population. But the difference is that in cluster sampling all the subjects of the selected subgroup are studied. While in stratified sampling, only randomly selected subjects of subgroups are studied.

Cluster Sampling is a probability sampling method where the target population is divided into clusters. Some of these clusters are selected randomly for sampling and all the members are studied under each randomly selected cluster.

Stratified Sampling is a probability sampling method, in which a population is divided into unique, homogeneous strata, members from these strata are randomly selected to form a sample.

7 0

3 years ago

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