Solve for B. R = x(A + B) A) B = (R - A)/x B) B = (A - Rx)/x C) B = (R

2x - 5y = - 15

UkoKoshka [18]

Answer:

2x+15=5y

y=(2x+15)/5

hope this helps

7 0

3 years ago

Read 2 more answers

Find the solution of the system of equations. -5x+3y=3 -4x+3y=3

allochka39001 [22]

Answer:

your answer is (0,1)

Step-by-step explanation:

3 0

3 years ago

Please help!!!! (don’t comment for free points, this isn’t the place)

Allushta [10]

tan 44 = h/ x

x = 15 ft * sin 26

so

h = x * tan 44

= (15 ft * sin 26) (tan 44 )

so the anser is D

hope this would help you

5 0

4 years ago

Read 2 more answers

Math help please Thanks A lot

babunello [35]

Answer:

2 hours: 3968 [I don't understand the $ sign in the answer box]

At midnight: 12137

Step-by-step explanation:

The bacteria are increasing by 15% every hour. So for every hour we will have what we started with, plus 15% more.

The "15% more" can be represented mathematically with (1 + 0.15) or 1.15. Let's call this the "growth factor" and assign it the variable b. b is (1 + percent increase).

Since this per hour, in 1 hour we'll have (3000)*(1.15) = 3450

At the end of the second hour we're increased by 15% again:

(3450)*(1.15) = 3968.

Each additional hour add another (1.15) factor, If we assign a to be the starting population, this can be represented by:

P = a(1.15)^t for this sample that increase 15% per hour. t is time, in hours.

If a represents the growth factor, and P is the total population, the general expression is

P = ab^t

Using this for a = 3000 and b = 1.15, we can find the total population at midnight after starting at 2PM. That is a 10 hour period, so t = 10

P = (3000)*(1.15)^10

P = 12137

8 0

3 years ago

How to know if a function is periodic without graphing it ?

zhenek [66]

A function $f(t)$ is periodic if there is some constant $k$ such that $f(t+k)=f(k)$ for all $t$ in the domain of $f(t)$ . Then $k$ is the "period" of $f(t)$ .

Example:

If $f(x)=\sin x$ , then we have $\sin(x+2\pi)=\sin x\cos2\pi+\cos x\sin2\pi=\sin x$ , and so $\sin x$ is periodic with period $2\pi$ .

It gets a bit more complicated for a function like yours. We're looking for $k$ such that

$\pi\sin\left(\dfrac\pi2(t+k)\right)+1.8\cos\left(\dfrac{7\pi}5(t+k)\right)=\pi\sin\dfrac{\pi t}2+1.8\cos\dfrac{7\pi t}5$

Expanding on the left, you have

$\pi\sin\dfrac{\pi t}2\cos\dfrac{k\pi}2+\pi\cos\dfrac{\pi t}2\sin\dfrac{k\pi}2$

and

$1.8\cos\dfrac{7\pi t}5\cos\dfrac{7k\pi}5-1.8\sin\dfrac{7\pi t}5\sin\dfrac{7k\pi}5$

It follows that the following must be satisfied:

$\begin{cases}\cos\dfrac{k\pi}2=1\\\\\sin\dfrac{k\pi}2=0\\\\\cos\dfrac{7k\pi}5=1\\\\\sin\dfrac{7k\pi}5=0\end{cases}$

The first two equations are satisfied whenever $k\in\{0,\pm4,\pm8,\ldots\}$ , or more generally, when $k=4n$ and $n\in\mathbb Z$ (i.e. any multiple of 4).

The second two are satisfied whenever $k\in\left\{0,\pm\dfrac{10}7,\pm\dfrac{20}7,\ldots\right\}$ , and more generally when $k=\dfrac{10n}7$ with $n\in\mathbb Z$ (any multiple of 10/7).

It then follows that all four equations will be satisfied whenever the two sets above intersect. This happens when $k$ is any common multiple of 4 and 10/7. The least positive one would be 20, which means the period for your function is 20.

Let's verify:

$\sin\left(\dfrac\pi2(t+20)\right)=\sin\dfrac{\pi t}2\underbrace{\cos10\pi}_1+\cos\dfrac{\pi t}2\underbrace{\sin10\pi}_0=\sin\dfrac{\pi t}2$

$\cos\left(\dfrac{7\pi}5(t+20)\right)=\cos\dfrac{7\pi t}5\underbrace{\cos28\pi}_1-\sin\dfrac{7\pi t}5\underbrace{\sin28\pi}_0=\cos\dfrac{7\pi t}5$

More generally, it can be shown that

$f(t)=\displaystyle\sum_{i=1}^n(a_i\sin(b_it)+c_i\cos(d_it))$

is periodic with period $\mbox{lcm}(b_1,\ldots,b_n,d_1,\ldots,d_n)$ .

4 0

3 years ago

Solve for B. R = x(A + B) A) B = (R - A)/x B) B = (A - Rx)/x C) B = (R - Ax)/x